feat: websearch quota enhancements and balance notify hint

- QuotaLimit changed to *int64 (null=unlimited, >0=limited)
- Add reset-usage endpoint (POST /admin/settings/web-search-emulation/reset-usage)
- Show quota usage in header always (collapsed and expanded)
- Add reset quota button in expanded provider view
- Quota input: empty=unlimited with ∞ placeholder, must be >0 if set
- Add email verification hint on balance notify card

backend/cmd/server/VERSION

@@ -1 +1 @@
-0.1.112.3
+0.1.112.4

backend/internal/handler/admin/setting_handler.go

@@ -1962,7 +1962,28 @@ func (h *SettingHandler) UpdateWebSearchEmulationConfig(c *gin.Context) {
 		response.ErrorFrom(c, err)
 		return
 	}
-	response.Success(c, service.SanitizeWebSearchConfig(c.Request.Context(), updated))
+	response.Success(c, service.PopulateWebSearchUsage(c.Request.Context(), updated))
+}
+
+// ResetWebSearchUsage 重置指定 provider 的配额用量
+// POST /api/v1/admin/settings/web-search-emulation/reset-usage
+func (h *SettingHandler) ResetWebSearchUsage(c *gin.Context) {
+	var req struct {
+		ProviderType string `json:"provider_type"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request: "+err.Error())
+		return
+	}
+	if req.ProviderType == "" {
+		response.BadRequest(c, "provider_type is required")
+		return
+	}
+	if err := service.ResetWebSearchUsage(c.Request.Context(), req.ProviderType); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Success(c, nil)
 }
 
 // TestWebSearchEmulation 测试 Web Search 搜索

backend/internal/pkg/websearch/manager.go

@@ -447,6 +447,15 @@ func (m *Manager) GetAllUsage(ctx context.Context) map[string]int64 {
 	return result
 }
 
+// ResetUsage deletes the Redis quota key for the given provider, resetting usage to 0.
+func (m *Manager) ResetUsage(ctx context.Context, providerType string) error {
+	if m.redis == nil {
+		return nil
+	}
+	key := quotaRedisKey(providerType)
+	return m.redis.Del(ctx, key).Err()
+}
+
 // --- Provider factory ---
 
 func (m *Manager) buildProvider(cfg ProviderConfig, client *http.Client) Provider {

backend/internal/server/http.go

@@ -73,7 +73,7 @@ func ProvideRouter(
 			pc := websearch.ProviderConfig{
 				Type:       p.Type,
 				APIKey:     p.APIKey,
-				QuotaLimit: p.QuotaLimit,
+				QuotaLimit: derefInt64(p.QuotaLimit),
 				ExpiresAt:  p.ExpiresAt,
 			}
 			if p.SubscribedAt != nil {
@@ -141,3 +141,10 @@ func ProvideHTTPServer(cfg *config.Config, router *gin.Engine) *http.Server {
 		// 不设置 ReadTimeout，因为大请求体可能需要较长时间读取
 	}
 }
+
+func derefInt64(p *int64) int64 {
+	if p == nil {
+		return 0
+	}
+	return *p
+}

backend/internal/server/routes/admin.go

@@ -411,6 +411,7 @@ func registerSettingsRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
 		adminSettings.GET("/web-search-emulation", h.Admin.Setting.GetWebSearchEmulationConfig)
 		adminSettings.PUT("/web-search-emulation", h.Admin.Setting.UpdateWebSearchEmulationConfig)
 		adminSettings.POST("/web-search-emulation/test", h.Admin.Setting.TestWebSearchEmulation)
+		adminSettings.POST("/web-search-emulation/reset-usage", h.Admin.Setting.ResetWebSearchUsage)
 	}
 }
 

backend/internal/service/websearch_config.go

@@ -24,7 +24,7 @@ type WebSearchProviderConfig struct {
 	Type             string `json:"type"`                    // websearch.ProviderTypeBrave | Tavily
 	APIKey           string `json:"api_key,omitempty"`       // secret — omitted in API responses
 	APIKeyConfigured bool   `json:"api_key_configured"`      // read-only mask
-	QuotaLimit       int64  `json:"quota_limit"`             // 0 = unlimited
+	QuotaLimit       *int64 `json:"quota_limit"`             // nil = unlimited, >0 = limited
 	SubscribedAt     *int64 `json:"subscribed_at,omitempty"` // subscription start (unix seconds); quota resets monthly
 	QuotaUsed        int64  `json:"quota_used,omitempty"`    // read-only: current usage from Redis
 	ProxyID          *int64 `json:"proxy_id"`                // optional proxy association
@@ -52,8 +52,8 @@ func validateWebSearchConfig(cfg *WebSearchEmulationConfig) error {
 		if !validProviderTypes[p.Type] {
 			return fmt.Errorf("provider[%d]: invalid type %q", i, p.Type)
 		}
-		if p.QuotaLimit < 0 {
-			return fmt.Errorf("provider[%d]: quota_limit must be >= 0", i)
+		if p.QuotaLimit != nil && *p.QuotaLimit < 0 {
+			return fmt.Errorf("provider[%d]: quota_limit must be > 0 or null", i)
 		}
 		if seen[p.Type] {
 			return fmt.Errorf("provider[%d]: duplicate type %q", i, p.Type)
@@ -299,6 +299,15 @@ func PopulateWebSearchUsage(ctx context.Context, cfg *WebSearchEmulationConfig)
 	return &out
 }
 
+// ResetWebSearchUsage deletes the Redis quota key for the given provider type.
+func ResetWebSearchUsage(ctx context.Context, providerType string) error {
+	mgr := getWebSearchManager()
+	if mgr == nil {
+		return fmt.Errorf("web search manager not initialized")
+	}
+	return mgr.ResetUsage(ctx, providerType)
+}
+
 // SanitizeWebSearchConfig returns a copy with api_key fields masked and quota usage populated.
 func SanitizeWebSearchConfig(ctx context.Context, cfg *WebSearchEmulationConfig) *WebSearchEmulationConfig {
 	if cfg == nil {

backend/internal/service/websearch_config_test.go

@@ -17,8 +17,8 @@ func TestValidateWebSearchConfig_Valid(t *testing.T) {
 	cfg := &WebSearchEmulationConfig{
 		Enabled: true,
 		Providers: []WebSearchProviderConfig{
-			{Type: "brave", QuotaLimit: 1000},
-			{Type: "tavily", QuotaLimit: 500},
+			{Type: "brave", QuotaLimit: int64Ptr(1000)},
+			{Type: "tavily", QuotaLimit: int64Ptr(500)},
 		},
 	}
 	require.NoError(t, validateWebSearchConfig(cfg))
@@ -42,9 +42,9 @@ func TestValidateWebSearchConfig_InvalidType(t *testing.T) {
 
 func TestValidateWebSearchConfig_NegativeQuotaLimit(t *testing.T) {
 	cfg := &WebSearchEmulationConfig{
-		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: -1}},
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: int64Ptr(-1)}},
 	}
-	require.ErrorContains(t, validateWebSearchConfig(cfg), "quota_limit must be >= 0")
+	require.ErrorContains(t, validateWebSearchConfig(cfg), "quota_limit must be > 0 or null")
 }
 
 func TestValidateWebSearchConfig_DuplicateType(t *testing.T) {
@@ -57,9 +57,9 @@ func TestValidateWebSearchConfig_DuplicateType(t *testing.T) {
 	require.ErrorContains(t, validateWebSearchConfig(cfg), "duplicate type")
 }
 
-func TestValidateWebSearchConfig_ZeroQuotaLimit(t *testing.T) {
+func TestValidateWebSearchConfig_NilQuotaLimit(t *testing.T) {
 	cfg := &WebSearchEmulationConfig{
-		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: 0}},
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: nil}},
 	}
 	require.NoError(t, validateWebSearchConfig(cfg))
 }
@@ -92,7 +92,7 @@ func TestParseWebSearchConfigJSON_BackwardCompatibility(t *testing.T) {
 	cfg := parseWebSearchConfigJSON(raw)
 	require.True(t, cfg.Enabled)
 	require.Len(t, cfg.Providers, 1)
-	require.Equal(t, int64(1000), cfg.Providers[0].QuotaLimit)
+	require.Equal(t, int64(1000), *cfg.Providers[0].QuotaLimit)
 }
 
 // --- SanitizeWebSearchConfig ---
@@ -126,12 +126,12 @@ func TestSanitizeWebSearchConfig_PreservesOtherFields(t *testing.T) {
 	cfg := &WebSearchEmulationConfig{
 		Enabled: true,
 		Providers: []WebSearchProviderConfig{
-			{Type: "brave", APIKey: "secret", QuotaLimit: 1000},
+			{Type: "brave", APIKey: "secret", QuotaLimit: int64Ptr(1000)},
 		},
 	}
 	out := SanitizeWebSearchConfig(context.Background(), cfg)
 	require.True(t, out.Enabled)
-	require.Equal(t, int64(1000), out.Providers[0].QuotaLimit)
+	require.Equal(t, int64(1000), *out.Providers[0].QuotaLimit)
 }
 
 func TestSanitizeWebSearchConfig_DoesNotMutateOriginal(t *testing.T) {