feat(affiliate): add feature toggle and per-user custom invite settings

- 在系统设置「功能开关」中新增邀请返利总开关，默认关闭；
  关闭态：菜单隐藏、注册忽略 aff、新充值不返利，但已有 quota 仍可转余额
- 支持管理员为指定用户设置专属邀请码（覆盖随机码，全局唯一）
- 支持管理员为指定用户设置专属返利比例（覆盖全局比例，可单条/批量调整）
- 在系统设置邀请返利卡片内嵌入专属用户管理表格（搜索/编辑/批量/删除），
  删除采用项目通用 ConfirmDialog，会同时清除专属比例并把邀请码重置为系统随机码
- /affiliate 用户页新增「我的返利比例」卡片与动态使用说明，让用户直观看到
  分享后能拿到多少（同源 resolveRebateRatePercent 计算，与实际充值一致）
- 新增数据库迁移 132 添加 aff_rebate_rate_percent 与 aff_code_custom 列
- 新增 admin 路由组 /api/v1/admin/affiliates/users/* 共 5 个端点
- AffiliateService 改为只依赖 *SettingService，去除冗余的 SettingRepository
- 邀请码格式校验放宽到 [A-Z0-9_-]{4,32}，兼容旧 12 位系统码与新自定义码
- 补充单元测试与集成测试覆盖新方法、冲突路径与边界值

backend/cmd/server/wire_gen.go

@@ -70,7 +70,7 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	promoService := service.NewPromoService(promoCodeRepository, userRepository, billingCacheService, client, apiKeyAuthCacheInvalidator)
 	subscriptionService := service.NewSubscriptionService(groupRepository, userSubscriptionRepository, billingCacheService, client, configConfig)
 	affiliateRepository := repository.NewAffiliateRepository(client, db)
-	affiliateService := service.NewAffiliateService(affiliateRepository, settingRepository, apiKeyAuthCacheInvalidator, billingCacheService)
+	affiliateService := service.NewAffiliateService(affiliateRepository, settingService, apiKeyAuthCacheInvalidator, billingCacheService)
 	authService := service.NewAuthService(client, userRepository, redeemCodeRepository, refreshTokenCache, configConfig, settingService, emailService, turnstileService, emailQueueService, promoService, subscriptionService, affiliateService)
 	userService := service.NewUserService(userRepository, settingRepository, apiKeyAuthCacheInvalidator, billingCache)
 	redeemCache := repository.NewRedeemCache(redisClient)
@@ -231,7 +231,8 @@ func initializeApplication(buildInfo handler.BuildInfo) (*Application, error) {
 	channelMonitorRequestTemplateService := service.NewChannelMonitorRequestTemplateService(channelMonitorRequestTemplateRepository)
 	channelMonitorRequestTemplateHandler := admin.NewChannelMonitorRequestTemplateHandler(channelMonitorRequestTemplateService)
 	paymentHandler := admin.NewPaymentHandler(paymentService, paymentConfigService)
-	adminHandlers := handler.ProvideAdminHandlers(dashboardHandler, adminUserHandler, groupHandler, accountHandler, adminAnnouncementHandler, dataManagementHandler, backupHandler, oAuthHandler, openAIOAuthHandler, geminiOAuthHandler, antigravityOAuthHandler, proxyHandler, adminRedeemHandler, promoHandler, settingHandler, opsHandler, systemHandler, adminSubscriptionHandler, adminUsageHandler, userAttributeHandler, errorPassthroughHandler, tlsFingerprintProfileHandler, adminAPIKeyHandler, scheduledTestHandler, channelHandler, channelMonitorHandler, channelMonitorRequestTemplateHandler, paymentHandler)
+	affiliateHandler := admin.NewAffiliateHandler(affiliateService, adminService)
+	adminHandlers := handler.ProvideAdminHandlers(dashboardHandler, adminUserHandler, groupHandler, accountHandler, adminAnnouncementHandler, dataManagementHandler, backupHandler, oAuthHandler, openAIOAuthHandler, geminiOAuthHandler, antigravityOAuthHandler, proxyHandler, adminRedeemHandler, promoHandler, settingHandler, opsHandler, systemHandler, adminSubscriptionHandler, adminUsageHandler, userAttributeHandler, errorPassthroughHandler, tlsFingerprintProfileHandler, adminAPIKeyHandler, scheduledTestHandler, channelHandler, channelMonitorHandler, channelMonitorRequestTemplateHandler, paymentHandler, affiliateHandler)
 	usageRecordWorkerPool := service.NewUsageRecordWorkerPool(configConfig)
 	userMsgQueueCache := repository.NewUserMsgQueueCache(redisClient)
 	userMessageQueueService := service.ProvideUserMessageQueueService(userMsgQueueCache, rpmCache, configConfig)

backend/internal/handler/admin/affiliate_handler.go

@@ -0,0 +1,183 @@
+package admin
+
+import (
+	"strconv"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+
+	"github.com/gin-gonic/gin"
+)
+
+// AffiliateHandler handles admin affiliate (邀请返利) management:
+// listing users with custom settings, updating per-user invite codes
+// and exclusive rebate rates, and batch operations.
+type AffiliateHandler struct {
+	affiliateService *service.AffiliateService
+	adminService     service.AdminService
+}
+
+// NewAffiliateHandler creates a new admin affiliate handler.
+func NewAffiliateHandler(affiliateService *service.AffiliateService, adminService service.AdminService) *AffiliateHandler {
+	return &AffiliateHandler{
+		affiliateService: affiliateService,
+		adminService:     adminService,
+	}
+}
+
+// ListUsers returns paginated users with custom affiliate settings.
+// GET /api/v1/admin/affiliates/users
+func (h *AffiliateHandler) ListUsers(c *gin.Context) {
+	page, pageSize := response.ParsePagination(c)
+	search := c.Query("search")
+
+	entries, total, err := h.affiliateService.AdminListCustomUsers(c.Request.Context(), service.AffiliateAdminFilter{
+		Search:   search,
+		Page:     page,
+		PageSize: pageSize,
+	})
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Paginated(c, entries, total, page, pageSize)
+}
+
+// UpdateUserSettings updates a user's affiliate settings.
+// PUT /api/v1/admin/affiliates/users/:user_id
+//
+// Both fields are optional and applied independently.
+type UpdateAffiliateUserRequest struct {
+	AffCode              *string  `json:"aff_code"`
+	AffRebateRatePercent *float64 `json:"aff_rebate_rate_percent"`
+	// ClearRebateRate explicitly clears the per-user rate (sets it to NULL).
+	// Used to disambiguate from "field not provided".
+	ClearRebateRate bool `json:"clear_rebate_rate"`
+}
+
+func (h *AffiliateHandler) UpdateUserSettings(c *gin.Context) {
+	userID, err := strconv.ParseInt(c.Param("user_id"), 10, 64)
+	if err != nil || userID <= 0 {
+		response.BadRequest(c, "Invalid user_id")
+		return
+	}
+
+	var req UpdateAffiliateUserRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request: "+err.Error())
+		return
+	}
+
+	if req.AffCode != nil {
+		if err := h.affiliateService.AdminUpdateUserAffCode(c.Request.Context(), userID, *req.AffCode); err != nil {
+			response.ErrorFrom(c, err)
+			return
+		}
+	}
+
+	if req.ClearRebateRate {
+		if err := h.affiliateService.AdminSetUserRebateRate(c.Request.Context(), userID, nil); err != nil {
+			response.ErrorFrom(c, err)
+			return
+		}
+	} else if req.AffRebateRatePercent != nil {
+		if err := h.affiliateService.AdminSetUserRebateRate(c.Request.Context(), userID, req.AffRebateRatePercent); err != nil {
+			response.ErrorFrom(c, err)
+			return
+		}
+	}
+
+	response.Success(c, gin.H{"user_id": userID})
+}
+
+// ClearUserSettings removes ALL of a user's custom affiliate settings — clears
+// the exclusive rebate rate AND regenerates the invite code as a new system
+// random one. Conceptually this "removes the user from the custom list".
+//
+// Both writes happen in this handler; failure of one leaves the other applied,
+// but the operation is idempotent so the admin can re-run it safely.
+// DELETE /api/v1/admin/affiliates/users/:user_id
+func (h *AffiliateHandler) ClearUserSettings(c *gin.Context) {
+	userID, err := strconv.ParseInt(c.Param("user_id"), 10, 64)
+	if err != nil || userID <= 0 {
+		response.BadRequest(c, "Invalid user_id")
+		return
+	}
+	if err := h.affiliateService.AdminSetUserRebateRate(c.Request.Context(), userID, nil); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	if _, err := h.affiliateService.AdminResetUserAffCode(c.Request.Context(), userID); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Success(c, gin.H{"user_id": userID})
+}
+
+// BatchSetRate applies the same rebate rate (or clears it) to multiple users.
+//
+// Protocol: pass `clear: true` to clear rates (aff_rebate_rate_percent is
+// ignored). Otherwise aff_rebate_rate_percent is required and applied to
+// every user_id. The explicit `clear` flag exists because Go's JSON unmarshal
+// can't distinguish a missing field from `null`, and a silent clear from a
+// frontend that forgot to include the rate would be a footgun.
+//
+// POST /api/v1/admin/affiliates/users/batch-rate
+type BatchSetRateRequest struct {
+	UserIDs              []int64  `json:"user_ids" binding:"required"`
+	AffRebateRatePercent *float64 `json:"aff_rebate_rate_percent"`
+	Clear                bool     `json:"clear"`
+}
+
+func (h *AffiliateHandler) BatchSetRate(c *gin.Context) {
+	var req BatchSetRateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request: "+err.Error())
+		return
+	}
+	if len(req.UserIDs) == 0 {
+		response.BadRequest(c, "user_ids cannot be empty")
+		return
+	}
+	if !req.Clear && req.AffRebateRatePercent == nil {
+		response.BadRequest(c, "aff_rebate_rate_percent is required unless clear=true")
+		return
+	}
+	rate := req.AffRebateRatePercent
+	if req.Clear {
+		rate = nil
+	}
+	if err := h.affiliateService.AdminBatchSetUserRebateRate(c.Request.Context(), req.UserIDs, rate); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Success(c, gin.H{"affected": len(req.UserIDs)})
+}
+
+// AffiliateUserSummary is the minimal user shape returned by LookupUsers,
+// shared with the frontend's add-custom-user picker.
+type AffiliateUserSummary struct {
+	ID       int64  `json:"id"`
+	Email    string `json:"email"`
+	Username string `json:"username"`
+}
+
+// LookupUsers searches users by email/username for the "add custom user" modal.
+// GET /api/v1/admin/affiliates/users/lookup?q=
+func (h *AffiliateHandler) LookupUsers(c *gin.Context) {
+	keyword := c.Query("q")
+	if keyword == "" {
+		response.Success(c, []AffiliateUserSummary{})
+		return
+	}
+	users, _, err := h.adminService.ListUsers(c.Request.Context(), 1, 20, service.UserListFilters{Search: keyword}, "email", "asc")
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	result := make([]AffiliateUserSummary, len(users))
+	for i, u := range users {
+		result[i] = AffiliateUserSummary{ID: u.ID, Email: u.Email, Username: u.Username}
+	}
+	response.Success(c, result)
+}

backend/internal/handler/admin/setting_handler.go

@@ -242,6 +242,8 @@ func (h *SettingHandler) GetSettings(c *gin.Context) {
 		ChannelMonitorDefaultIntervalSeconds: settings.ChannelMonitorDefaultIntervalSeconds,
 
 		AvailableChannelsEnabled: settings.AvailableChannelsEnabled,
+
+		AffiliateEnabled: settings.AffiliateEnabled,
 	}
 	response.Success(c, systemSettingsResponseData(payload, authSourceDefaults))
 }
@@ -441,6 +443,9 @@ type UpdateSettingsRequest struct {
 
 	// Available Channels feature switch (user-facing)
 	AvailableChannelsEnabled *bool `json:"available_channels_enabled"`
+
+	// Affiliate (邀请返利) feature switch
+	AffiliateEnabled *bool `json:"affiliate_enabled"`
 }
 
 // UpdateSettings 更新系统设置
@@ -1265,6 +1270,12 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 			}
 			return previousSettings.AvailableChannelsEnabled
 		}(),
+		AffiliateEnabled: func() bool {
+			if req.AffiliateEnabled != nil {
+				return *req.AffiliateEnabled
+			}
+			return previousSettings.AffiliateEnabled
+		}(),
 	}
 
 	authSourceDefaults := &service.AuthSourceDefaultSettings{
@@ -1502,6 +1513,8 @@ func (h *SettingHandler) UpdateSettings(c *gin.Context) {
 		ChannelMonitorDefaultIntervalSeconds: updatedSettings.ChannelMonitorDefaultIntervalSeconds,
 
 		AvailableChannelsEnabled: updatedSettings.AvailableChannelsEnabled,
+
+		AffiliateEnabled: updatedSettings.AffiliateEnabled,
 	}
 	response.Success(c, systemSettingsResponseData(payload, updatedAuthSourceDefaults))
 }
@@ -1870,6 +1883,9 @@ func diffSettings(before *service.SystemSettings, after *service.SystemSettings,
 	if before.AvailableChannelsEnabled != after.AvailableChannelsEnabled {
 		changed = append(changed, "available_channels_enabled")
 	}
+	if before.AffiliateEnabled != after.AffiliateEnabled {
+		changed = append(changed, "affiliate_enabled")
+	}
 	changed = appendAuthSourceDefaultChanges(changed, beforeAuthSourceDefaults, afterAuthSourceDefaults)
 	return changed
 }

backend/internal/handler/dto/settings.go

@@ -192,6 +192,9 @@ type SystemSettings struct {
 
 	// Available Channels feature switch (user-facing aggregate view)
 	AvailableChannelsEnabled bool `json:"available_channels_enabled"`
+
+	// Affiliate (邀请返利) feature switch
+	AffiliateEnabled bool `json:"affiliate_enabled"`
 }
 
 type DefaultSubscriptionSetting struct {
@@ -244,6 +247,8 @@ type PublicSettings struct {
 	ChannelMonitorDefaultIntervalSeconds int  `json:"channel_monitor_default_interval_seconds"`
 
 	AvailableChannelsEnabled bool `json:"available_channels_enabled"`
+
+	AffiliateEnabled bool `json:"affiliate_enabled"`
 }
 
 // OverloadCooldownSettings 529过载冷却配置 DTO

backend/internal/handler/handler.go

@@ -34,6 +34,7 @@ type AdminHandlers struct {
 	ChannelMonitor         *admin.ChannelMonitorHandler
 	ChannelMonitorTemplate *admin.ChannelMonitorRequestTemplateHandler
 	Payment                *admin.PaymentHandler
+	Affiliate              *admin.AffiliateHandler
 }
 
 // Handlers contains all HTTP handlers

backend/internal/handler/setting_handler.go

@@ -75,5 +75,7 @@ func (h *SettingHandler) GetPublicSettings(c *gin.Context) {
 		ChannelMonitorDefaultIntervalSeconds: settings.ChannelMonitorDefaultIntervalSeconds,
 
 		AvailableChannelsEnabled: settings.AvailableChannelsEnabled,
+
+		AffiliateEnabled: settings.AffiliateEnabled,
 	})
 }

backend/internal/handler/wire.go

@@ -37,6 +37,7 @@ func ProvideAdminHandlers(
 	channelMonitorHandler *admin.ChannelMonitorHandler,
 	channelMonitorTemplateHandler *admin.ChannelMonitorRequestTemplateHandler,
 	paymentHandler *admin.PaymentHandler,
+	affiliateHandler *admin.AffiliateHandler,
 ) *AdminHandlers {
 	return &AdminHandlers{
 		Dashboard:              dashboardHandler,
@@ -67,6 +68,7 @@ func ProvideAdminHandlers(
 		ChannelMonitor:         channelMonitorHandler,
 		ChannelMonitorTemplate: channelMonitorTemplateHandler,
 		Payment:                paymentHandler,
+		Affiliate:              affiliateHandler,
 	}
 }
 
@@ -169,6 +171,7 @@ var ProviderSet = wire.NewSet(
 	admin.NewChannelMonitorHandler,
 	admin.NewChannelMonitorRequestTemplateHandler,
 	admin.NewPaymentHandler,
+	admin.NewAffiliateHandler,
 
 	// AdminHandlers and Handlers constructors
 	ProvideAdminHandlers,

backend/internal/repository/affiliate_repo.go

@@ -294,6 +294,8 @@ func queryAffiliateByUserID(ctx context.Context, client affiliateQueryExecer, us
 	rows, err := client.QueryContext(ctx, `
 SELECT user_id,
        aff_code,
+       aff_code_custom,
+       aff_rebate_rate_percent,
        inviter_id,
        aff_count,
        aff_quota::double precision,
@@ -315,9 +317,12 @@ WHERE user_id = $1`, userID)
 
 	var out service.AffiliateSummary
 	var inviterID sql.NullInt64
+	var rebateRate sql.NullFloat64
 	if err := rows.Scan(
 		&out.UserID,
 		&out.AffCode,
+		&out.AffCodeCustom,
+		&rebateRate,
 		&inviterID,
 		&out.AffCount,
 		&out.AffQuota,
@@ -330,6 +335,10 @@ WHERE user_id = $1`, userID)
 	if inviterID.Valid {
 		out.InviterID = &inviterID.Int64
 	}
+	if rebateRate.Valid {
+		v := rebateRate.Float64
+		out.AffRebateRatePercent = &v
+	}
 	return &out, nil
 }
 
@@ -337,6 +346,8 @@ func queryAffiliateByCode(ctx context.Context, client affiliateQueryExecer, code
 	rows, err := client.QueryContext(ctx, `
 SELECT user_id,
        aff_code,
+       aff_code_custom,
+       aff_rebate_rate_percent,
        inviter_id,
        aff_count,
        aff_quota::double precision,
@@ -360,9 +371,12 @@ LIMIT 1`, strings.ToUpper(strings.TrimSpace(code)))
 
 	var out service.AffiliateSummary
 	var inviterID sql.NullInt64
+	var rebateRate sql.NullFloat64
 	if err := rows.Scan(
 		&out.UserID,
 		&out.AffCode,
+		&out.AffCodeCustom,
+		&rebateRate,
 		&inviterID,
 		&out.AffCount,
 		&out.AffQuota,
@@ -375,6 +389,10 @@ LIMIT 1`, strings.ToUpper(strings.TrimSpace(code)))
 	if inviterID.Valid {
 		out.InviterID = &inviterID.Int64
 	}
+	if rebateRate.Valid {
+		v := rebateRate.Float64
+		out.AffRebateRatePercent = &v
+	}
 	return &out, nil
 }
 
@@ -418,3 +436,229 @@ func isAffiliateUniqueViolation(err error) bool {
 	}
 	return false
 }
+
+// UpdateUserAffCode 改写用户的邀请码（自定义专属邀请码）。
+// 唯一性冲突返回 ErrAffiliateCodeTaken。
+func (r *affiliateRepository) UpdateUserAffCode(ctx context.Context, userID int64, newCode string) error {
+	if userID <= 0 {
+		return service.ErrUserNotFound
+	}
+	code := strings.ToUpper(strings.TrimSpace(newCode))
+	if code == "" {
+		return service.ErrAffiliateCodeInvalid
+	}
+
+	return r.withTx(ctx, func(txCtx context.Context, txClient *dbent.Client) error {
+		if _, err := ensureUserAffiliateWithClient(txCtx, txClient, userID); err != nil {
+			return err
+		}
+		res, err := txClient.ExecContext(txCtx, `
+UPDATE user_affiliates
+SET aff_code = $1,
+    aff_code_custom = true,
+    updated_at = NOW()
+WHERE user_id = $2`, code, userID)
+		if err != nil {
+			if isAffiliateUniqueViolation(err) {
+				return service.ErrAffiliateCodeTaken
+			}
+			return fmt.Errorf("update aff_code: %w", err)
+		}
+		affected, _ := res.RowsAffected()
+		if affected == 0 {
+			return service.ErrUserNotFound
+		}
+		return nil
+	})
+}
+
+// ResetUserAffCode 把 aff_code 还原为系统随机码，并清除 aff_code_custom 标记。
+func (r *affiliateRepository) ResetUserAffCode(ctx context.Context, userID int64) (string, error) {
+	if userID <= 0 {
+		return "", service.ErrUserNotFound
+	}
+	var newCode string
+	err := r.withTx(ctx, func(txCtx context.Context, txClient *dbent.Client) error {
+		if _, err := ensureUserAffiliateWithClient(txCtx, txClient, userID); err != nil {
+			return err
+		}
+		for i := 0; i < affiliateCodeMaxAttempts; i++ {
+			candidate, codeErr := generateAffiliateCode()
+			if codeErr != nil {
+				return codeErr
+			}
+			res, err := txClient.ExecContext(txCtx, `
+UPDATE user_affiliates
+SET aff_code = $1,
+    aff_code_custom = false,
+    updated_at = NOW()
+WHERE user_id = $2`, candidate, userID)
+			if err != nil {
+				if isAffiliateUniqueViolation(err) {
+					continue
+				}
+				return fmt.Errorf("reset aff_code: %w", err)
+			}
+			affected, _ := res.RowsAffected()
+			if affected == 0 {
+				return service.ErrUserNotFound
+			}
+			newCode = candidate
+			return nil
+		}
+		return fmt.Errorf("reset aff_code: exhausted attempts")
+	})
+	if err != nil {
+		return "", err
+	}
+	return newCode, nil
+}
+
+// SetUserRebateRate 设置或清除用户专属返利比例。ratePercent==nil 表示清除（沿用全局）。
+func (r *affiliateRepository) SetUserRebateRate(ctx context.Context, userID int64, ratePercent *float64) error {
+	if userID <= 0 {
+		return service.ErrUserNotFound
+	}
+	return r.withTx(ctx, func(txCtx context.Context, txClient *dbent.Client) error {
+		if _, err := ensureUserAffiliateWithClient(txCtx, txClient, userID); err != nil {
+			return err
+		}
+		// nullableArg lets us use a single UPDATE for both "set value" and
+		// "clear" cases — database/sql converts nil interface{} to SQL NULL.
+		res, err := txClient.ExecContext(txCtx, `
+UPDATE user_affiliates
+SET aff_rebate_rate_percent = $1,
+    updated_at = NOW()
+WHERE user_id = $2`, nullableArg(ratePercent), userID)
+		if err != nil {
+			return fmt.Errorf("set aff_rebate_rate_percent: %w", err)
+		}
+		affected, _ := res.RowsAffected()
+		if affected == 0 {
+			return service.ErrUserNotFound
+		}
+		return nil
+	})
+}
+
+// BatchSetUserRebateRate 批量为多个用户设置专属比例（nil 清除）。
+func (r *affiliateRepository) BatchSetUserRebateRate(ctx context.Context, userIDs []int64, ratePercent *float64) error {
+	if len(userIDs) == 0 {
+		return nil
+	}
+	return r.withTx(ctx, func(txCtx context.Context, txClient *dbent.Client) error {
+		for _, uid := range userIDs {
+			if uid <= 0 {
+				continue
+			}
+			if _, err := ensureUserAffiliateWithClient(txCtx, txClient, uid); err != nil {
+				return err
+			}
+		}
+		_, err := txClient.ExecContext(txCtx, `
+UPDATE user_affiliates
+SET aff_rebate_rate_percent = $1,
+    updated_at = NOW()
+WHERE user_id = ANY($2)`, nullableArg(ratePercent), pq.Array(userIDs))
+		if err != nil {
+			return fmt.Errorf("batch set aff_rebate_rate_percent: %w", err)
+		}
+		return nil
+	})
+}
+
+// nullableArg unwraps a *float64 into an interface{} suitable for SQL parameter
+// binding: nil pointer → SQL NULL, non-nil → the float value.
+func nullableArg(v *float64) any {
+	if v == nil {
+		return nil
+	}
+	return *v
+}
+
+// ListUsersWithCustomSettings 列出有专属配置（自定义码或专属比例）的用户。
+//
+// 单一查询同时处理"无搜索"与"按邮箱/用户名模糊搜索"：
+// 空 search 时拼接出的 LIKE 模式为 "%%"，匹配所有行；非空时按 ILIKE 子串匹配。
+// 这避免了为两种情况维护两份 SQL 模板。
+func (r *affiliateRepository) ListUsersWithCustomSettings(ctx context.Context, filter service.AffiliateAdminFilter) ([]service.AffiliateAdminEntry, int64, error) {
+	page := filter.Page
+	if page < 1 {
+		page = 1
+	}
+	pageSize := filter.PageSize
+	if pageSize <= 0 || pageSize > 200 {
+		pageSize = 20
+	}
+	offset := (page - 1) * pageSize
+	likePattern := "%" + strings.TrimSpace(filter.Search) + "%"
+
+	const baseFrom = `
+FROM user_affiliates ua
+JOIN users u ON u.id = ua.user_id
+WHERE (ua.aff_code_custom = true OR ua.aff_rebate_rate_percent IS NOT NULL)
+  AND (u.email ILIKE $1 OR u.username ILIKE $1)`
+
+	client := clientFromContext(ctx, r.client)
+
+	total, err := scanInt64(ctx, client, "SELECT COUNT(*)"+baseFrom, likePattern)
+	if err != nil {
+		return nil, 0, fmt.Errorf("count affiliate admin entries: %w", err)
+	}
+
+	listQuery := `
+SELECT ua.user_id,
+       COALESCE(u.email, ''),
+       COALESCE(u.username, ''),
+       ua.aff_code,
+       ua.aff_code_custom,
+       ua.aff_rebate_rate_percent,
+       ua.aff_count` + baseFrom + `
+ORDER BY ua.updated_at DESC
+LIMIT $2 OFFSET $3`
+
+	rows, err := client.QueryContext(ctx, listQuery, likePattern, pageSize, offset)
+	if err != nil {
+		return nil, 0, fmt.Errorf("list affiliate admin entries: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	entries := make([]service.AffiliateAdminEntry, 0)
+	for rows.Next() {
+		var e service.AffiliateAdminEntry
+		var rebate sql.NullFloat64
+		if err := rows.Scan(&e.UserID, &e.Email, &e.Username, &e.AffCode,
+			&e.AffCodeCustom, &rebate, &e.AffCount); err != nil {
+			return nil, 0, err
+		}
+		if rebate.Valid {
+			v := rebate.Float64
+			e.AffRebateRatePercent = &v
+		}
+		entries = append(entries, e)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, 0, err
+	}
+	return entries, total, nil
+}
+
+// scanInt64 runs a query expected to return a single int64 column (e.g. COUNT).
+func scanInt64(ctx context.Context, client affiliateQueryExecer, query string, args ...any) (int64, error) {
+	rows, err := client.QueryContext(ctx, query, args...)
+	if err != nil {
+		return 0, err
+	}
+	defer func() { _ = rows.Close() }()
+	if !rows.Next() {
+		if err := rows.Err(); err != nil {
+			return 0, err
+		}
+		return 0, nil
+	}
+	var v int64
+	if err := rows.Scan(&v); err != nil {
+		return 0, err
+	}
+	return v, nil
+}

backend/internal/repository/affiliate_repo_integration_test.go

@@ -182,3 +182,218 @@ VALUES ($1, $2, 0, 0, NOW(), NOW())`, u.ID, affCode)
 		"SELECT balance::double precision FROM users WHERE id = $1", u.ID)
 	require.InDelta(t, 3.21, persistedBalance, 1e-9)
 }
+
+// TestAffiliateRepository_AdminCustomCode covers the success path of admin
+// invite-code rewrite + reset within a shared test transaction:
+// - UpdateUserAffCode replaces aff_code, sets aff_code_custom=true, lookup works
+// - the old code can no longer be found
+// - ResetUserAffCode reverts aff_code_custom and assigns a new system-format code
+//
+// The conflict path (duplicate code → ErrAffiliateCodeTaken) lives in its own
+// test because a unique-violation aborts the surrounding Postgres tx, which
+// would poison subsequent assertions in the same transaction.
+func TestAffiliateRepository_AdminCustomCode(t *testing.T) {
+	ctx := context.Background()
+	tx := testEntTx(t)
+	txCtx := dbent.NewTxContext(ctx, tx)
+	client := tx.Client()
+
+	repo := NewAffiliateRepository(client, integrationDB)
+
+	u := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-custom-%d@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser,
+		Status:       service.StatusActive,
+	})
+
+	original, err := repo.EnsureUserAffiliate(txCtx, u.ID)
+	require.NoError(t, err)
+	require.False(t, original.AffCodeCustom, "system-generated codes start as non-custom")
+	originalCode := original.AffCode
+
+	// Rewrite to a custom code
+	customCode := fmt.Sprintf("VIP%09d", time.Now().UnixNano()%1_000_000_000)
+	require.NoError(t, repo.UpdateUserAffCode(txCtx, u.ID, customCode))
+
+	updated, err := repo.EnsureUserAffiliate(txCtx, u.ID)
+	require.NoError(t, err)
+	require.Equal(t, customCode, updated.AffCode)
+	require.True(t, updated.AffCodeCustom)
+
+	// Lookup by new custom code finds the user
+	byCode, err := repo.GetAffiliateByCode(txCtx, customCode)
+	require.NoError(t, err)
+	require.Equal(t, u.ID, byCode.UserID)
+
+	// Old system code should no longer match
+	_, err = repo.GetAffiliateByCode(txCtx, originalCode)
+	require.ErrorIs(t, err, service.ErrAffiliateProfileNotFound)
+
+	// Reset back to a fresh system code, clears custom flag
+	newSysCode, err := repo.ResetUserAffCode(txCtx, u.ID)
+	require.NoError(t, err)
+	require.NotEqual(t, customCode, newSysCode)
+
+	reset, err := repo.EnsureUserAffiliate(txCtx, u.ID)
+	require.NoError(t, err)
+	require.Equal(t, newSysCode, reset.AffCode)
+	require.False(t, reset.AffCodeCustom)
+
+	// The old custom code is now free again
+	_, err = repo.GetAffiliateByCode(txCtx, customCode)
+	require.ErrorIs(t, err, service.ErrAffiliateProfileNotFound)
+}
+
+// TestAffiliateRepository_AdminCustomCode_Conflict isolates the unique-violation
+// path. PostgreSQL aborts the enclosing tx when a unique constraint fires, so
+// this test must be the only assertion and run in its own tx — production
+// callers each have their own outer tx, so this matches real behavior.
+func TestAffiliateRepository_AdminCustomCode_Conflict(t *testing.T) {
+	ctx := context.Background()
+	tx := testEntTx(t)
+	txCtx := dbent.NewTxContext(ctx, tx)
+	client := tx.Client()
+
+	repo := NewAffiliateRepository(client, integrationDB)
+
+	taker := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-conflict-taker-%d@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser, Status: service.StatusActive,
+	})
+	requester := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-conflict-req-%d@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser, Status: service.StatusActive,
+	})
+
+	takenCode := fmt.Sprintf("HOT%09d", time.Now().UnixNano()%1_000_000_000)
+	require.NoError(t, repo.UpdateUserAffCode(txCtx, taker.ID, takenCode))
+
+	// Now requester tries to grab the same code → conflict.
+	err := repo.UpdateUserAffCode(txCtx, requester.ID, takenCode)
+	require.ErrorIs(t, err, service.ErrAffiliateCodeTaken)
+}
+
+// TestAffiliateRepository_AdminRebateRate covers per-user exclusive rate
+// set/clear and the Batch variant including NULL semantics.
+func TestAffiliateRepository_AdminRebateRate(t *testing.T) {
+	ctx := context.Background()
+	tx := testEntTx(t)
+	txCtx := dbent.NewTxContext(ctx, tx)
+	client := tx.Client()
+
+	repo := NewAffiliateRepository(client, integrationDB)
+
+	u1 := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-rate-%d-a@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser,
+		Status:       service.StatusActive,
+	})
+	u2 := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-rate-%d-b@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser,
+		Status:       service.StatusActive,
+	})
+
+	// Set exclusive rate for u1
+	rate := 42.5
+	require.NoError(t, repo.SetUserRebateRate(txCtx, u1.ID, &rate))
+
+	got, err := repo.EnsureUserAffiliate(txCtx, u1.ID)
+	require.NoError(t, err)
+	require.NotNil(t, got.AffRebateRatePercent)
+	require.InDelta(t, 42.5, *got.AffRebateRatePercent, 1e-9)
+
+	// Clear exclusive rate
+	require.NoError(t, repo.SetUserRebateRate(txCtx, u1.ID, nil))
+	cleared, err := repo.EnsureUserAffiliate(txCtx, u1.ID)
+	require.NoError(t, err)
+	require.Nil(t, cleared.AffRebateRatePercent)
+
+	// Batch set both users
+	batchRate := 15.0
+	require.NoError(t, repo.BatchSetUserRebateRate(txCtx, []int64{u1.ID, u2.ID}, &batchRate))
+
+	for _, uid := range []int64{u1.ID, u2.ID} {
+		v, err := repo.EnsureUserAffiliate(txCtx, uid)
+		require.NoError(t, err)
+		require.NotNil(t, v.AffRebateRatePercent)
+		require.InDelta(t, 15.0, *v.AffRebateRatePercent, 1e-9)
+	}
+
+	// Batch clear
+	require.NoError(t, repo.BatchSetUserRebateRate(txCtx, []int64{u1.ID, u2.ID}, nil))
+	for _, uid := range []int64{u1.ID, u2.ID} {
+		v, err := repo.EnsureUserAffiliate(txCtx, uid)
+		require.NoError(t, err)
+		require.Nil(t, v.AffRebateRatePercent)
+	}
+}
+
+// TestAffiliateRepository_ListUsersWithCustomSettings verifies the admin list
+// only includes users with at least one override applied.
+func TestAffiliateRepository_ListUsersWithCustomSettings(t *testing.T) {
+	ctx := context.Background()
+	tx := testEntTx(t)
+	txCtx := dbent.NewTxContext(ctx, tx)
+	client := tx.Client()
+
+	repo := NewAffiliateRepository(client, integrationDB)
+
+	// User without any custom config — should NOT appear in the list.
+	plainEmail := fmt.Sprintf("affiliate-plain-%d@example.com", time.Now().UnixNano())
+	uPlain := mustCreateUser(t, client, &service.User{
+		Email: plainEmail, PasswordHash: "hash",
+		Role: service.RoleUser, Status: service.StatusActive,
+	})
+	_, err := repo.EnsureUserAffiliate(txCtx, uPlain.ID)
+	require.NoError(t, err)
+
+	// User with a custom code — should appear.
+	uCode := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-codeonly-%d@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser, Status: service.StatusActive,
+	})
+	require.NoError(t, repo.UpdateUserAffCode(txCtx, uCode.ID, fmt.Sprintf("VIP%09d", time.Now().UnixNano()%1_000_000_000)))
+
+	// User with only an exclusive rate — should appear.
+	uRate := mustCreateUser(t, client, &service.User{
+		Email:        fmt.Sprintf("affiliate-rateonly-%d@example.com", time.Now().UnixNano()),
+		PasswordHash: "hash",
+		Role:         service.RoleUser, Status: service.StatusActive,
+	})
+	r := 33.3
+	require.NoError(t, repo.SetUserRebateRate(txCtx, uRate.ID, &r))
+
+	entries, total, err := repo.ListUsersWithCustomSettings(txCtx, service.AffiliateAdminFilter{
+		Page: 1, PageSize: 100,
+	})
+	require.NoError(t, err)
+
+	// Build a quick lookup to assert per-user attributes (other tests may have
+	// inserted custom rows in the same DB; we only care about our 3).
+	byUserID := make(map[int64]service.AffiliateAdminEntry, len(entries))
+	for _, e := range entries {
+		byUserID[e.UserID] = e
+	}
+
+	require.NotContains(t, byUserID, uPlain.ID, "users without overrides must not appear")
+
+	codeEntry, ok := byUserID[uCode.ID]
+	require.True(t, ok, "custom-code user missing from list")
+	require.True(t, codeEntry.AffCodeCustom)
+	require.Nil(t, codeEntry.AffRebateRatePercent)
+
+	rateEntry, ok := byUserID[uRate.ID]
+	require.True(t, ok, "custom-rate user missing from list")
+	require.False(t, rateEntry.AffCodeCustom)
+	require.NotNil(t, rateEntry.AffRebateRatePercent)
+	require.InDelta(t, 33.3, *rateEntry.AffRebateRatePercent, 1e-9)
+
+	require.GreaterOrEqual(t, total, int64(2), "total must include at least our 2 custom rows")
+}

backend/internal/server/api_contract_test.go

@@ -775,6 +775,7 @@ func TestAPIContracts(t *testing.T) {
 					"channel_monitor_enabled": true,
 					"channel_monitor_default_interval_seconds": 60,
 					"available_channels_enabled": false,
+					"affiliate_enabled": false,
 					"wechat_connect_enabled": false,
 					"wechat_connect_app_id": "",
 					"wechat_connect_app_secret_configured": false,
@@ -951,6 +952,7 @@ func TestAPIContracts(t *testing.T) {
 					"channel_monitor_enabled": true,
 					"channel_monitor_default_interval_seconds": 60,
 					"available_channels_enabled": false,
+					"affiliate_enabled": false,
 					"wechat_connect_enabled": true,
 					"wechat_connect_app_id": "wx-open-config",
 					"wechat_connect_app_secret_configured": true,

backend/internal/server/routes/admin.go

@@ -91,6 +91,9 @@ func RegisterAdminRoutes(
 
 		// 渠道监控
 		registerChannelMonitorRoutes(admin, h)
+
+		// 邀请返利（专属用户管理）
+		registerAffiliateRoutes(admin, h)
 	}
 }
 
@@ -594,3 +597,18 @@ func registerChannelMonitorRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
 		templates.POST("/:id/apply", h.Admin.ChannelMonitorTemplate.Apply)
 	}
 }
+
+// registerAffiliateRoutes 注册邀请返利的管理端路由（专属用户配置）
+func registerAffiliateRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
+	affiliates := admin.Group("/affiliates")
+	{
+		users := affiliates.Group("/users")
+		{
+			users.GET("", h.Admin.Affiliate.ListUsers)
+			users.GET("/lookup", h.Admin.Affiliate.LookupUsers)
+			users.POST("/batch-rate", h.Admin.Affiliate.BatchSetRate)
+			users.PUT("/:user_id", h.Admin.Affiliate.UpdateUserSettings)
+			users.DELETE("/:user_id", h.Admin.Affiliate.ClearUserSettings)
+		}
+	}
+}

backend/internal/service/affiliate_service.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"errors"
 	"math"
-	"strconv"
 	"strings"
 	"time"
 
@@ -15,28 +14,39 @@ import (
 var (
 	ErrAffiliateProfileNotFound = infraerrors.NotFound("AFFILIATE_PROFILE_NOT_FOUND", "affiliate profile not found")
 	ErrAffiliateCodeInvalid     = infraerrors.BadRequest("AFFILIATE_CODE_INVALID", "invalid affiliate code")
+	ErrAffiliateCodeTaken       = infraerrors.Conflict("AFFILIATE_CODE_TAKEN", "affiliate code already in use")
 	ErrAffiliateAlreadyBound    = infraerrors.Conflict("AFFILIATE_ALREADY_BOUND", "affiliate inviter already bound")
 	ErrAffiliateQuotaEmpty      = infraerrors.BadRequest("AFFILIATE_QUOTA_EMPTY", "no affiliate quota available to transfer")
 )
 
 const (
 	affiliateInviteesLimit = 100
-	// affiliateCodeFormatLength must stay in sync with repository.affiliateCodeLength.
-	affiliateCodeFormatLength = 12
+	// AffiliateCodeMinLength / AffiliateCodeMaxLength bound both system-generated
+	// 12-char codes and admin-customized codes (e.g. "VIP2026").
+	AffiliateCodeMinLength = 4
+	AffiliateCodeMaxLength = 32
 )
 
-// affiliateCodeValidChar is a 256-entry lookup table mirroring the charset used
-// by the repository's generateAffiliateCode (A-Z minus I/O, digits 2-9).
+// affiliateCodeValidChar accepts uppercase letters, digits, underscore and dash.
+// All input passes through strings.ToUpper before validation, so lowercase from
+// users is normalized — admins may supply mixed case in their UI.
 var affiliateCodeValidChar = func() [256]bool {
 	var tbl [256]bool
-	for _, c := range []byte("ABCDEFGHJKLMNPQRSTUVWXYZ23456789") {
+	for c := byte('A'); c <= 'Z'; c++ {
 		tbl[c] = true
 	}
+	for c := byte('0'); c <= '9'; c++ {
+		tbl[c] = true
+	}
+	tbl['_'] = true
+	tbl['-'] = true
 	return tbl
 }()
 
+// isValidAffiliateCodeFormat validates code format for both binding (user input)
+// and admin updates. Caller is expected to upper-case the input first.
 func isValidAffiliateCodeFormat(code string) bool {
-	if len(code) != affiliateCodeFormatLength {
+	if len(code) < AffiliateCodeMinLength || len(code) > AffiliateCodeMaxLength {
 		return false
 	}
 	for i := 0; i < len(code); i++ {
@@ -48,14 +58,16 @@ func isValidAffiliateCodeFormat(code string) bool {
 }
 
 type AffiliateSummary struct {
-	UserID          int64     `json:"user_id"`
-	AffCode         string    `json:"aff_code"`
-	InviterID       *int64    `json:"inviter_id,omitempty"`
-	AffCount        int       `json:"aff_count"`
-	AffQuota        float64   `json:"aff_quota"`
-	AffHistoryQuota float64   `json:"aff_history_quota"`
-	CreatedAt       time.Time `json:"created_at"`
-	UpdatedAt       time.Time `json:"updated_at"`
+	UserID               int64     `json:"user_id"`
+	AffCode              string    `json:"aff_code"`
+	AffCodeCustom        bool      `json:"aff_code_custom"`
+	AffRebateRatePercent *float64  `json:"aff_rebate_rate_percent,omitempty"`
+	InviterID            *int64    `json:"inviter_id,omitempty"`
+	AffCount             int       `json:"aff_count"`
+	AffQuota             float64   `json:"aff_quota"`
+	AffHistoryQuota      float64   `json:"aff_history_quota"`
+	CreatedAt            time.Time `json:"created_at"`
+	UpdatedAt            time.Time `json:"updated_at"`
 }
 
 type AffiliateInvitee struct {
@@ -72,7 +84,11 @@ type AffiliateDetail struct {
 	AffCount        int                `json:"aff_count"`
 	AffQuota        float64            `json:"aff_quota"`
 	AffHistoryQuota float64            `json:"aff_history_quota"`
-	Invitees        []AffiliateInvitee `json:"invitees"`
+	// EffectiveRebateRatePercent 是当前用户作为邀请人时实际生效的返利比例：
+	// 优先用户自己的专属比例（aff_rebate_rate_percent），否则回退到全局比例。
+	// 用于在用户的 /affiliate 页面直观展示「分享后能拿到多少」。
+	EffectiveRebateRatePercent float64            `json:"effective_rebate_rate_percent"`
+	Invitees                   []AffiliateInvitee `json:"invitees"`
 }
 
 type AffiliateRepository interface {
@@ -82,24 +98,57 @@ type AffiliateRepository interface {
 	AccrueQuota(ctx context.Context, inviterID, inviteeUserID int64, amount float64) (bool, error)
 	TransferQuotaToBalance(ctx context.Context, userID int64) (float64, float64, error)
 	ListInvitees(ctx context.Context, inviterID int64, limit int) ([]AffiliateInvitee, error)
+
+	// 管理端：用户级专属配置
+	UpdateUserAffCode(ctx context.Context, userID int64, newCode string) error
+	ResetUserAffCode(ctx context.Context, userID int64) (string, error)
+	SetUserRebateRate(ctx context.Context, userID int64, ratePercent *float64) error
+	BatchSetUserRebateRate(ctx context.Context, userIDs []int64, ratePercent *float64) error
+	ListUsersWithCustomSettings(ctx context.Context, filter AffiliateAdminFilter) ([]AffiliateAdminEntry, int64, error)
+}
+
+// AffiliateAdminFilter 列表筛选条件
+type AffiliateAdminFilter struct {
+	Search   string
+	Page     int
+	PageSize int
+}
+
+// AffiliateAdminEntry 专属用户列表条目
+type AffiliateAdminEntry struct {
+	UserID               int64    `json:"user_id"`
+	Email                string   `json:"email"`
+	Username             string   `json:"username"`
+	AffCode              string   `json:"aff_code"`
+	AffCodeCustom        bool     `json:"aff_code_custom"`
+	AffRebateRatePercent *float64 `json:"aff_rebate_rate_percent,omitempty"`
+	AffCount             int      `json:"aff_count"`
 }
 
 type AffiliateService struct {
 	repo                 AffiliateRepository
-	settingRepo          SettingRepository
+	settingService       *SettingService
 	authCacheInvalidator APIKeyAuthCacheInvalidator
 	billingCacheService  *BillingCacheService
 }
 
-func NewAffiliateService(repo AffiliateRepository, settingRepo SettingRepository, authCacheInvalidator APIKeyAuthCacheInvalidator, billingCacheService *BillingCacheService) *AffiliateService {
+func NewAffiliateService(repo AffiliateRepository, settingService *SettingService, authCacheInvalidator APIKeyAuthCacheInvalidator, billingCacheService *BillingCacheService) *AffiliateService {
 	return &AffiliateService{
 		repo:                 repo,
-		settingRepo:          settingRepo,
+		settingService:       settingService,
 		authCacheInvalidator: authCacheInvalidator,
 		billingCacheService:  billingCacheService,
 	}
 }
 
+// IsEnabled reports whether the affiliate (邀请返利) feature is turned on.
+func (s *AffiliateService) IsEnabled(ctx context.Context) bool {
+	if s == nil || s.settingService == nil {
+		return AffiliateEnabledDefault
+	}
+	return s.settingService.IsAffiliateEnabled(ctx)
+}
+
 func (s *AffiliateService) EnsureUserAffiliate(ctx context.Context, userID int64) (*AffiliateSummary, error) {
 	if userID <= 0 {
 		return nil, infraerrors.BadRequest("INVALID_USER", "invalid user")
@@ -120,13 +169,14 @@ func (s *AffiliateService) GetAffiliateDetail(ctx context.Context, userID int64)
 		return nil, err
 	}
 	return &AffiliateDetail{
-		UserID:          summary.UserID,
-		AffCode:         summary.AffCode,
-		InviterID:       summary.InviterID,
-		AffCount:        summary.AffCount,
-		AffQuota:        summary.AffQuota,
-		AffHistoryQuota: summary.AffHistoryQuota,
-		Invitees:        invitees,
+		UserID:                     summary.UserID,
+		AffCode:                    summary.AffCode,
+		InviterID:                  summary.InviterID,
+		AffCount:                   summary.AffCount,
+		AffQuota:                   summary.AffQuota,
+		AffHistoryQuota:            summary.AffHistoryQuota,
+		EffectiveRebateRatePercent: s.resolveRebateRatePercent(ctx, summary),
+		Invitees:                   invitees,
 	}, nil
 }
 
@@ -135,12 +185,16 @@ func (s *AffiliateService) BindInviterByCode(ctx context.Context, userID int64,
 	if code == "" {
 		return nil
 	}
-	if !isValidAffiliateCodeFormat(code) {
-		return ErrAffiliateCodeInvalid
-	}
 	if s == nil || s.repo == nil {
 		return infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
 	}
+	// 总开关关闭时，注册阶段静默忽略 aff 参数（不报错，避免阻断注册流程）
+	if !s.IsEnabled(ctx) {
+		return nil
+	}
+	if !isValidAffiliateCodeFormat(code) {
+		return ErrAffiliateCodeInvalid
+	}
 
 	selfSummary, err := s.repo.EnsureUserAffiliate(ctx, userID)
 	if err != nil {
@@ -178,6 +232,10 @@ func (s *AffiliateService) AccrueInviteRebate(ctx context.Context, inviteeUserID
 	if inviteeUserID <= 0 || baseRechargeAmount <= 0 || math.IsNaN(baseRechargeAmount) || math.IsInf(baseRechargeAmount, 0) {
 		return 0, nil
 	}
+	// 总开关关闭时，新充值不再产生返利
+	if !s.IsEnabled(ctx) {
+		return 0, nil
+	}
 
 	inviteeSummary, err := s.repo.EnsureUserAffiliate(ctx, inviteeUserID)
 	if err != nil {
@@ -187,16 +245,17 @@ func (s *AffiliateService) AccrueInviteRebate(ctx context.Context, inviteeUserID
 		return 0, nil
 	}
 
-	rebateRatePercent := s.loadAffiliateRebateRatePercent(ctx)
+	// 加载邀请人 profile，优先使用专属比例（覆盖全局）
+	inviterSummary, err := s.repo.EnsureUserAffiliate(ctx, *inviteeSummary.InviterID)
+	if err != nil {
+		return 0, err
+	}
+	rebateRatePercent := s.resolveRebateRatePercent(ctx, inviterSummary)
 	rebate := roundTo(baseRechargeAmount*(rebateRatePercent/100), 8)
 	if rebate <= 0 {
 		return 0, nil
 	}
 
-	if _, err := s.repo.EnsureUserAffiliate(ctx, *inviteeSummary.InviterID); err != nil {
-		return 0, err
-	}
-
 	applied, err := s.repo.AccrueQuota(ctx, *inviteeSummary.InviterID, inviteeUserID, rebate)
 	if err != nil {
 		return 0, err
@@ -207,6 +266,28 @@ func (s *AffiliateService) AccrueInviteRebate(ctx context.Context, inviteeUserID
 	return rebate, nil
 }
 
+// resolveRebateRatePercent returns the inviter's exclusive rate when set,
+// otherwise the global setting value (clamped to [Min, Max]).
+func (s *AffiliateService) resolveRebateRatePercent(ctx context.Context, inviter *AffiliateSummary) float64 {
+	if inviter != nil && inviter.AffRebateRatePercent != nil {
+		v := *inviter.AffRebateRatePercent
+		if math.IsNaN(v) || math.IsInf(v, 0) {
+			return s.globalRebateRatePercent(ctx)
+		}
+		return clampAffiliateRebateRate(v)
+	}
+	return s.globalRebateRatePercent(ctx)
+}
+
+// globalRebateRatePercent reads the system-wide rebate rate via SettingService,
+// returning the documented default when SettingService is unavailable.
+func (s *AffiliateService) globalRebateRatePercent(ctx context.Context) float64 {
+	if s == nil || s.settingService == nil {
+		return AffiliateRebateRateDefault
+	}
+	return s.settingService.GetAffiliateRebateRatePercent(ctx)
+}
+
 func (s *AffiliateService) TransferAffiliateQuota(ctx context.Context, userID int64) (float64, float64, error) {
 	if s == nil || s.repo == nil {
 		return 0, 0, infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
@@ -236,32 +317,6 @@ func (s *AffiliateService) listInvitees(ctx context.Context, inviterID int64) ([
 	return invitees, nil
 }
 
-func (s *AffiliateService) loadAffiliateRebateRatePercent(ctx context.Context) float64 {
-	if s == nil || s.settingRepo == nil {
-		return AffiliateRebateRateDefault
-	}
-
-	raw, err := s.settingRepo.GetValue(ctx, SettingKeyAffiliateRebateRate)
-	if err != nil {
-		return AffiliateRebateRateDefault
-	}
-
-	rate, err := strconv.ParseFloat(strings.TrimSpace(raw), 64)
-	if err != nil {
-		return AffiliateRebateRateDefault
-	}
-	if math.IsNaN(rate) || math.IsInf(rate, 0) {
-		return AffiliateRebateRateDefault
-	}
-	if rate < AffiliateRebateRateMin {
-		return AffiliateRebateRateMin
-	}
-	if rate > AffiliateRebateRateMax {
-		return AffiliateRebateRateMax
-	}
-	return rate
-}
-
 func roundTo(v float64, scale int) float64 {
 	factor := math.Pow10(scale)
 	return math.Round(v*factor) / factor
@@ -312,3 +367,82 @@ func (s *AffiliateService) invalidateAffiliateCaches(ctx context.Context, userID
 		}
 	}
 }
+
+// =========================
+// Admin: 专属配置管理
+// =========================
+
+// validateExclusiveRate ensures a per-user override is finite and within
+// [Min, Max]. nil is always valid (means "clear / fall back to global").
+func validateExclusiveRate(ratePercent *float64) error {
+	if ratePercent == nil {
+		return nil
+	}
+	v := *ratePercent
+	if math.IsNaN(v) || math.IsInf(v, 0) {
+		return infraerrors.BadRequest("INVALID_RATE", "invalid rebate rate")
+	}
+	if v < AffiliateRebateRateMin || v > AffiliateRebateRateMax {
+		return infraerrors.BadRequest("INVALID_RATE", "rebate rate out of range")
+	}
+	return nil
+}
+
+// AdminUpdateUserAffCode 管理员改写用户的邀请码（专属邀请码）。
+func (s *AffiliateService) AdminUpdateUserAffCode(ctx context.Context, userID int64, rawCode string) error {
+	if s == nil || s.repo == nil {
+		return infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
+	}
+	code := strings.ToUpper(strings.TrimSpace(rawCode))
+	if !isValidAffiliateCodeFormat(code) {
+		return ErrAffiliateCodeInvalid
+	}
+	return s.repo.UpdateUserAffCode(ctx, userID, code)
+}
+
+// AdminResetUserAffCode 重置用户邀请码为系统随机码。
+func (s *AffiliateService) AdminResetUserAffCode(ctx context.Context, userID int64) (string, error) {
+	if s == nil || s.repo == nil {
+		return "", infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
+	}
+	return s.repo.ResetUserAffCode(ctx, userID)
+}
+
+// AdminSetUserRebateRate 设置/清除用户专属返利比例。ratePercent==nil 表示清除。
+func (s *AffiliateService) AdminSetUserRebateRate(ctx context.Context, userID int64, ratePercent *float64) error {
+	if s == nil || s.repo == nil {
+		return infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
+	}
+	if err := validateExclusiveRate(ratePercent); err != nil {
+		return err
+	}
+	return s.repo.SetUserRebateRate(ctx, userID, ratePercent)
+}
+
+// AdminBatchSetUserRebateRate 批量设置/清除用户专属返利比例。
+func (s *AffiliateService) AdminBatchSetUserRebateRate(ctx context.Context, userIDs []int64, ratePercent *float64) error {
+	if s == nil || s.repo == nil {
+		return infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
+	}
+	if err := validateExclusiveRate(ratePercent); err != nil {
+		return err
+	}
+	cleaned := make([]int64, 0, len(userIDs))
+	for _, uid := range userIDs {
+		if uid > 0 {
+			cleaned = append(cleaned, uid)
+		}
+	}
+	if len(cleaned) == 0 {
+		return nil
+	}
+	return s.repo.BatchSetUserRebateRate(ctx, cleaned, ratePercent)
+}
+
+// AdminListCustomUsers 列出有专属配置的用户。
+func (s *AffiliateService) AdminListCustomUsers(ctx context.Context, filter AffiliateAdminFilter) ([]AffiliateAdminEntry, int64, error) {
+	if s == nil || s.repo == nil {
+		return nil, 0, infraerrors.ServiceUnavailable("SERVICE_UNAVAILABLE", "affiliate service unavailable")
+	}
+	return s.repo.ListUsersWithCustomSettings(ctx, filter)
+}

backend/internal/service/affiliate_service_test.go

@@ -4,51 +4,82 @@ package service
 
 import (
 	"context"
+	"math"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
-type affiliateSettingRepoStub struct {
-	value string
-	err   error
-}
-
-func (s *affiliateSettingRepoStub) Get(context.Context, string) (*Setting, error) { return nil, s.err }
-func (s *affiliateSettingRepoStub) GetValue(context.Context, string) (string, error) {
-	if s.err != nil {
-		return "", s.err
-	}
-	return s.value, nil
-}
-func (s *affiliateSettingRepoStub) Set(context.Context, string, string) error { return s.err }
-func (s *affiliateSettingRepoStub) GetMultiple(context.Context, []string) (map[string]string, error) {
-	if s.err != nil {
-		return nil, s.err
-	}
-	return map[string]string{}, nil
-}
-func (s *affiliateSettingRepoStub) SetMultiple(context.Context, map[string]string) error {
-	return s.err
-}
-func (s *affiliateSettingRepoStub) GetAll(context.Context) (map[string]string, error) {
-	if s.err != nil {
-		return nil, s.err
-	}
-	return map[string]string{}, nil
-}
-func (s *affiliateSettingRepoStub) Delete(context.Context, string) error { return s.err }
-
-func TestAffiliateRebateRatePercentSemantics(t *testing.T) {
+// TestResolveRebateRatePercent_PerUserOverride verifies that per-inviter
+// AffRebateRatePercent overrides the global rate, that NULL falls back to the
+// global rate, and that out-of-range exclusive rates are clamped silently.
+//
+// SettingService is left nil here so globalRebateRatePercent returns the
+// documented default (AffiliateRebateRateDefault = 20%) — this exercises the
+// fallback path without spinning up a settings stub.
+func TestResolveRebateRatePercent_PerUserOverride(t *testing.T) {
 	t.Parallel()
+	svc := &AffiliateService{}
 
-	svc := &AffiliateService{settingRepo: &affiliateSettingRepoStub{value: "1"}}
-	rate := svc.loadAffiliateRebateRatePercent(context.Background())
-	require.Equal(t, 1.0, rate)
+	// nil exclusive rate → falls back to global default (20%)
+	require.InDelta(t, AffiliateRebateRateDefault,
+		svc.resolveRebateRatePercent(context.Background(), &AffiliateSummary{}), 1e-9)
 
-	svc.settingRepo = &affiliateSettingRepoStub{value: "0.2"}
-	rate = svc.loadAffiliateRebateRatePercent(context.Background())
-	require.Equal(t, 0.2, rate)
+	// exclusive rate set → overrides global
+	rate := 50.0
+	require.InDelta(t, 50.0,
+		svc.resolveRebateRatePercent(context.Background(), &AffiliateSummary{AffRebateRatePercent: &rate}), 1e-9)
+
+	// exclusive rate 0 → returns 0 (no rebate, intentional)
+	zero := 0.0
+	require.InDelta(t, 0.0,
+		svc.resolveRebateRatePercent(context.Background(), &AffiliateSummary{AffRebateRatePercent: &zero}), 1e-9)
+
+	// exclusive rate above max → clamped to Max
+	tooHigh := 250.0
+	require.InDelta(t, AffiliateRebateRateMax,
+		svc.resolveRebateRatePercent(context.Background(), &AffiliateSummary{AffRebateRatePercent: &tooHigh}), 1e-9)
+
+	// exclusive rate below min → clamped to Min
+	tooLow := -5.0
+	require.InDelta(t, AffiliateRebateRateMin,
+		svc.resolveRebateRatePercent(context.Background(), &AffiliateSummary{AffRebateRatePercent: &tooLow}), 1e-9)
+}
+
+// TestIsEnabled_NilSettingServiceReturnsDefault verifies that IsEnabled
+// safely handles a nil settingService dependency by returning the default
+// (off). This protects callers from nil-pointer crashes in misconfigured
+// environments.
+func TestIsEnabled_NilSettingServiceReturnsDefault(t *testing.T) {
+	t.Parallel()
+	svc := &AffiliateService{}
+	require.False(t, svc.IsEnabled(context.Background()))
+	require.Equal(t, AffiliateEnabledDefault, svc.IsEnabled(context.Background()))
+}
+
+// TestValidateExclusiveRate_BoundaryAndInvalid covers the validator used by
+// admin-facing rate setters: nil is always valid (clear), in-range values
+// are accepted, NaN/Inf and out-of-range values produce a typed BadRequest.
+func TestValidateExclusiveRate_BoundaryAndInvalid(t *testing.T) {
+	t.Parallel()
+	require.NoError(t, validateExclusiveRate(nil))
+
+	for _, v := range []float64{0, 0.01, 50, 99.99, 100} {
+		v := v
+		require.NoError(t, validateExclusiveRate(&v), "value %v should be valid", v)
+	}
+
+	for _, v := range []float64{-0.01, 100.01, -100, 200} {
+		v := v
+		require.Error(t, validateExclusiveRate(&v), "value %v should be rejected", v)
+	}
+
+	nan := math.NaN()
+	require.Error(t, validateExclusiveRate(&nan))
+	posInf := math.Inf(1)
+	require.Error(t, validateExclusiveRate(&posInf))
+	negInf := math.Inf(-1)
+	require.Error(t, validateExclusiveRate(&negInf))
 }
 
 func TestMaskEmail(t *testing.T) {
@@ -61,24 +92,33 @@ func TestMaskEmail(t *testing.T) {
 func TestIsValidAffiliateCodeFormat(t *testing.T) {
 	t.Parallel()
 
+	// 邀请码格式校验同时服务于：
+	// 1) 系统自动生成的 12 位随机码（A-Z 去 I/O，2-9 去 0/1）
+	// 2) 管理员设置的自定义专属码（如 "VIP2026"、"NEW_USER-1"）
+	// 因此校验放宽到 [A-Z0-9_-]{4,32}（要求调用方先 ToUpper）。
 	cases := []struct {
 		name string
 		in   string
 		want bool
 	}{
-		{"valid canonical", "ABCDEFGHJKLM", true},
+		{"valid canonical 12-char", "ABCDEFGHJKLM", true},
 		{"valid all digits 2-9", "234567892345", true},
 		{"valid mixed", "A2B3C4D5E6F7", true},
-		{"too short", "ABCDEFGHJKL", false},
-		{"too long", "ABCDEFGHJKLMN", false},
-		{"contains excluded letter I", "IBCDEFGHJKLM", false},
-		{"contains excluded letter O", "OBCDEFGHJKLM", false},
-		{"contains excluded digit 0", "0BCDEFGHJKLM", false},
-		{"contains excluded digit 1", "1BCDEFGHJKLM", false},
+		{"valid admin custom short", "VIP1", true},
+		{"valid admin custom with hyphen", "NEW-USER", true},
+		{"valid admin custom with underscore", "VIP_2026", true},
+		{"valid 32-char max", "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345", true},
+		// Previously-excluded chars (I/O/0/1) are now allowed since admins may use them.
+		{"letter I now allowed", "IBCDEFGHJKLM", true},
+		{"letter O now allowed", "OBCDEFGHJKLM", true},
+		{"digit 0 now allowed", "0BCDEFGHJKLM", true},
+		{"digit 1 now allowed", "1BCDEFGHJKLM", true},
+		{"too short (3 chars)", "ABC", false},
+		{"too long (33 chars)", "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456", false},
 		{"lowercase rejected (caller must ToUpper first)", "abcdefghjklm", false},
 		{"empty", "", false},
-		{"12-byte utf8 non-ascii", "ÄÄÄÄÄÄ", false}, // 6×2 bytes = 12 bytes, bytes out of charset
-		{"ascii punctuation", "ABCDEFGHJK.M", false},
+		{"utf8 non-ascii", "ÄÄÄÄÄÄ", false}, // bytes out of charset
+		{"ascii punctuation .", "ABCDEFGHJK.M", false},
 		{"whitespace", "ABCDEFGHJK M", false},
 	}
 	for _, tc := range cases {

backend/internal/service/domain_constants.go

@@ -23,6 +23,7 @@ const (
 	AffiliateRebateRateDefault = 20.0
 	AffiliateRebateRateMin     = 0.0
 	AffiliateRebateRateMax     = 100.0
+	AffiliateEnabledDefault    = false // 邀请返利总开关默认关闭
 )
 
 // Platform constants
@@ -94,6 +95,7 @@ const (
 	SettingKeyPasswordResetEnabled             = "password_reset_enabled"              // 是否启用忘记密码功能（需要先开启邮件验证）
 	SettingKeyFrontendURL                      = "frontend_url"                        // 前端基础URL，用于生成邮件中的重置密码链接
 	SettingKeyInvitationCodeEnabled            = "invitation_code_enabled"             // 是否启用邀请码注册
+	SettingKeyAffiliateEnabled                 = "affiliate_enabled"                   // 邀请返利功能总开关
 	SettingKeyAffiliateRebateRate              = "affiliate_rebate_rate"               // 邀请返利比例（百分比，0-100）
 
 	// 邮件服务设置

backend/internal/service/setting_service.go

@@ -454,6 +454,7 @@ func (s *SettingService) GetPublicSettings(ctx context.Context) (*PublicSettings
 		SettingKeyChannelMonitorEnabled,
 		SettingKeyChannelMonitorDefaultIntervalSeconds,
 		SettingKeyAvailableChannelsEnabled,
+		SettingKeyAffiliateEnabled,
 	}
 
 	settings, err := s.settingRepo.GetMultiple(ctx, keys)
@@ -541,6 +542,8 @@ func (s *SettingService) GetPublicSettings(ctx context.Context) (*PublicSettings
 		ChannelMonitorDefaultIntervalSeconds: parseChannelMonitorInterval(settings[SettingKeyChannelMonitorDefaultIntervalSeconds]),
 
 		AvailableChannelsEnabled: settings[SettingKeyAvailableChannelsEnabled] == "true",
+
+		AffiliateEnabled: settings[SettingKeyAffiliateEnabled] == "true",
 	}, nil
 }
 
@@ -687,6 +690,7 @@ type PublicSettingsInjectionPayload struct {
 	ChannelMonitorEnabled                bool `json:"channel_monitor_enabled"`
 	ChannelMonitorDefaultIntervalSeconds int  `json:"channel_monitor_default_interval_seconds"`
 	AvailableChannelsEnabled             bool `json:"available_channels_enabled"`
+	AffiliateEnabled                     bool `json:"affiliate_enabled"`
 }
 
 // GetPublicSettingsForInjection returns public settings in a format suitable for HTML injection.
@@ -739,6 +743,7 @@ func (s *SettingService) GetPublicSettingsForInjection(ctx context.Context) (any
 		ChannelMonitorEnabled:                settings.ChannelMonitorEnabled,
 		ChannelMonitorDefaultIntervalSeconds: settings.ChannelMonitorDefaultIntervalSeconds,
 		AvailableChannelsEnabled:             settings.AvailableChannelsEnabled,
+		AffiliateEnabled:                     settings.AffiliateEnabled,
 	}, nil
 }
 
@@ -1205,6 +1210,9 @@ func (s *SettingService) buildSystemSettingsUpdates(ctx context.Context, setting
 	// Available channels feature switch
 	updates[SettingKeyAvailableChannelsEnabled] = strconv.FormatBool(settings.AvailableChannelsEnabled)
 
+	// Affiliate (邀请返利) feature switch
+	updates[SettingKeyAffiliateEnabled] = strconv.FormatBool(settings.AffiliateEnabled)
+
 	// Claude Code version check
 	updates[SettingKeyMinClaudeCodeVersion] = settings.MinClaudeCodeVersion
 	updates[SettingKeyMaxClaudeCodeVersion] = settings.MaxClaudeCodeVersion
@@ -1480,6 +1488,30 @@ func (s *SettingService) IsInvitationCodeEnabled(ctx context.Context) bool {
 	return value == "true"
 }
 
+// IsAffiliateEnabled 检查是否启用邀请返利功能（总开关）
+func (s *SettingService) IsAffiliateEnabled(ctx context.Context) bool {
+	value, err := s.settingRepo.GetValue(ctx, SettingKeyAffiliateEnabled)
+	if err != nil {
+		return false // 默认关闭
+	}
+	return value == "true"
+}
+
+// GetAffiliateRebateRatePercent 读取并 clamp 全局返利比例。
+// 解析失败、缺失或越界都回退到 AffiliateRebateRateDefault — 该比例从不抛错，
+// 调用方只关心一个可用的数值。
+func (s *SettingService) GetAffiliateRebateRatePercent(ctx context.Context) float64 {
+	raw, err := s.settingRepo.GetValue(ctx, SettingKeyAffiliateRebateRate)
+	if err != nil {
+		return AffiliateRebateRateDefault
+	}
+	rate, err := strconv.ParseFloat(strings.TrimSpace(raw), 64)
+	if err != nil || math.IsNaN(rate) || math.IsInf(rate, 0) {
+		return AffiliateRebateRateDefault
+	}
+	return clampAffiliateRebateRate(rate)
+}
+
 // IsPasswordResetEnabled 检查是否启用密码重置功能
 // 要求：必须同时开启邮件验证
 func (s *SettingService) IsPasswordResetEnabled(ctx context.Context) bool {
@@ -1771,6 +1803,9 @@ func (s *SettingService) InitializeDefaultSettings(ctx context.Context) error {
 		// Available channels feature (default disabled; opt-in)
 		SettingKeyAvailableChannelsEnabled: "false",
 
+		// Affiliate (邀请返利) feature (default disabled; opt-in)
+		SettingKeyAffiliateEnabled: "false",
+
 		// Claude Code version check (default: empty = disabled)
 		SettingKeyMinClaudeCodeVersion: "",
 		SettingKeyMaxClaudeCodeVersion: "",
@@ -2091,6 +2126,9 @@ func (s *SettingService) parseSettings(settings map[string]string) *SystemSettin
 	// Available channels feature (default: disabled; strict true)
 	result.AvailableChannelsEnabled = settings[SettingKeyAvailableChannelsEnabled] == "true"
 
+	// Affiliate (邀请返利) feature (default: disabled; strict true)
+	result.AffiliateEnabled = settings[SettingKeyAffiliateEnabled] == "true"
+
 	// Claude Code version check
 	result.MinClaudeCodeVersion = settings[SettingKeyMinClaudeCodeVersion]
 	result.MaxClaudeCodeVersion = settings[SettingKeyMaxClaudeCodeVersion]

backend/internal/service/settings_view.go

@@ -106,6 +106,7 @@ type SystemSettings struct {
 
 	DefaultConcurrency   int
 	DefaultBalance       float64
+	AffiliateEnabled     bool
 	AffiliateRebateRate  float64
 	DefaultUserRPMLimit  int
 	DefaultSubscriptions []DefaultSubscriptionSetting
@@ -225,6 +226,9 @@ type PublicSettings struct {
 
 	// Available Channels feature (user-facing aggregate view)
 	AvailableChannelsEnabled bool `json:"available_channels_enabled"`
+
+	// Affiliate (邀请返利) feature toggle
+	AffiliateEnabled bool `json:"affiliate_enabled"`
 }
 
 type WeChatConnectOAuthConfig struct {

backend/migrations/132_affiliate_custom_settings.sql

@@ -0,0 +1,16 @@
+-- 邀请返利：用户专属配置增强
+-- 1) aff_rebate_rate_percent: 用户作为邀请人时的专属返利比例（百分比，NULL 表示沿用全局比例）
+-- 2) aff_code_custom: 标记当前 aff_code 是否被管理员手动改写过（用于"专属用户"列表筛选）
+
+ALTER TABLE user_affiliates
+    ADD COLUMN IF NOT EXISTS aff_rebate_rate_percent DECIMAL(5,2);
+
+ALTER TABLE user_affiliates
+    ADD COLUMN IF NOT EXISTS aff_code_custom BOOLEAN NOT NULL DEFAULT false;
+
+CREATE INDEX IF NOT EXISTS idx_user_affiliates_admin_settings
+    ON user_affiliates (updated_at)
+    WHERE aff_code_custom = true OR aff_rebate_rate_percent IS NOT NULL;
+
+COMMENT ON COLUMN user_affiliates.aff_rebate_rate_percent IS '专属返利比例（百分比 0-100，NULL 表示沿用全局）';
+COMMENT ON COLUMN user_affiliates.aff_code_custom IS '邀请码是否由管理员改写过（用于专属用户筛选）';