chore(channels): drop admin-side available channels view

Remove the admin-side "Available Channels" aggregate view — admins
already see full channel configuration (groups, pricing, model
mappings) in the channel edit dialog, making a read-only admin
aggregate view redundant. The user-side "可用渠道" remains.

Backend:
- Delete handler/admin/available_channel_handler.go (+ test)
- Drop AdminHandlers.AvailableChannel field and wire injection
- Remove /admin/channels/available route

Frontend:
- Delete views/admin/AvailableChannelsView.vue
- Drop /admin/available-channels router entry
- Strip AvailableChannel types + listAvailable from api/admin/channels.ts

backend/internal/handler/admin/available_channel_handler.go

@@ -1,95 +0,0 @@
-package admin
-
-import (
-	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
-	"github.com/Wei-Shaw/sub2api/internal/service"
-
-	"github.com/gin-gonic/gin"
-)
-
-// AvailableChannelHandler 处理「可用渠道」聚合视图的管理员接口。
-//
-// 该视图以只读方式聚合渠道基础信息、关联分组与推导出的支持模型列表（无通配符）。
-type AvailableChannelHandler struct {
-	channelService *service.ChannelService
-}
-
-// NewAvailableChannelHandler 创建 AvailableChannelHandler 实例。
-func NewAvailableChannelHandler(channelService *service.ChannelService) *AvailableChannelHandler {
-	return &AvailableChannelHandler{channelService: channelService}
-}
-
-// availableGroupResponse 响应中的分组概要。
-type availableGroupResponse struct {
-	ID       int64  `json:"id"`
-	Name     string `json:"name"`
-	Platform string `json:"platform"`
-}
-
-// supportedModelResponse 响应中的支持模型条目。
-type supportedModelResponse struct {
-	Name     string                       `json:"name"`
-	Platform string                       `json:"platform"`
-	Pricing  *channelModelPricingResponse `json:"pricing"`
-}
-
-// availableChannelResponse 管理员视图完整字段集。
-type availableChannelResponse struct {
-	ID                 int64                    `json:"id"`
-	Name               string                   `json:"name"`
-	Description        string                   `json:"description"`
-	Status             string                   `json:"status"`
-	BillingModelSource string                   `json:"billing_model_source"`
-	RestrictModels     bool                     `json:"restrict_models"`
-	Groups             []availableGroupResponse `json:"groups"`
-	SupportedModels    []supportedModelResponse `json:"supported_models"`
-}
-
-// availableChannelToAdminResponse 将 service 层的 AvailableChannel 转为管理员 DTO。
-// 同 package 内复用；也用于构造测试 fixture。
-func availableChannelToAdminResponse(ch service.AvailableChannel) availableChannelResponse {
-	groups := make([]availableGroupResponse, 0, len(ch.Groups))
-	for _, g := range ch.Groups {
-		groups = append(groups, availableGroupResponse{ID: g.ID, Name: g.Name, Platform: g.Platform})
-	}
-	models := make([]supportedModelResponse, 0, len(ch.SupportedModels))
-	for i := range ch.SupportedModels {
-		m := ch.SupportedModels[i]
-		var pricing *channelModelPricingResponse
-		if m.Pricing != nil {
-			p := pricingToResponse(m.Pricing)
-			pricing = &p
-		}
-		models = append(models, supportedModelResponse{
-			Name:     m.Name,
-			Platform: m.Platform,
-			Pricing:  pricing,
-		})
-	}
-	return availableChannelResponse{
-		ID:                 ch.ID,
-		Name:               ch.Name,
-		Description:        ch.Description,
-		Status:             ch.Status,
-		BillingModelSource: ch.BillingModelSource,
-		RestrictModels:     ch.RestrictModels,
-		Groups:             groups,
-		SupportedModels:    models,
-	}
-}
-
-// List 列出所有可用渠道（管理员视图）。
-// GET /api/v1/admin/channels/available
-func (h *AvailableChannelHandler) List(c *gin.Context) {
-	channels, err := h.channelService.ListAvailable(c.Request.Context())
-	if err != nil {
-		response.ErrorFrom(c, err)
-		return
-	}
-
-	out := make([]availableChannelResponse, 0, len(channels))
-	for _, ch := range channels {
-		out = append(out, availableChannelToAdminResponse(ch))
-	}
-	response.Success(c, gin.H{"items": out})
-}

backend/internal/handler/admin/available_channel_handler_test.go

@@ -1,57 +0,0 @@
-//go:build unit
-
-package admin
-
-import (
-	"encoding/json"
-	"testing"
-
-	"github.com/Wei-Shaw/sub2api/internal/service"
-	"github.com/stretchr/testify/require"
-)
-
-func TestAvailableChannelToAdminResponse_IncludesFullDTO(t *testing.T) {
-	// 管理员视图应包含 id / status / billing_model_source / restrict_models 等
-	// 管理字段；mapper 是纯透传，BillingModelSource 的默认回填由 service 层负责。
-	input := service.AvailableChannel{
-		ID:                 42,
-		Name:               "ch",
-		Description:        "d",
-		Status:             service.StatusActive,
-		BillingModelSource: service.BillingModelSourceChannelMapped,
-		RestrictModels:     true,
-		Groups: []service.AvailableGroupRef{
-			{ID: 1, Name: "g1", Platform: "anthropic"},
-		},
-		SupportedModels: []service.SupportedModel{
-			{Name: "claude-sonnet-4-6", Platform: "anthropic"},
-		},
-	}
-
-	resp := availableChannelToAdminResponse(input)
-	require.Equal(t, int64(42), resp.ID)
-	require.Equal(t, "ch", resp.Name)
-	require.Equal(t, service.StatusActive, resp.Status)
-	require.Equal(t, service.BillingModelSourceChannelMapped, resp.BillingModelSource)
-	require.True(t, resp.RestrictModels)
-	require.Len(t, resp.Groups, 1)
-	require.Len(t, resp.SupportedModels, 1)
-
-	// JSON 层验证管理字段确实会被序列化。
-	raw, err := json.Marshal(resp)
-	require.NoError(t, err)
-	var decoded map[string]any
-	require.NoError(t, json.Unmarshal(raw, &decoded))
-	for _, key := range []string{"id", "status", "billing_model_source", "restrict_models", "groups", "supported_models"} {
-		_, exists := decoded[key]
-		require.Truef(t, exists, "admin DTO must expose %q", key)
-	}
-}
-
-func TestAvailableChannelToAdminResponse_PreservesExplicitBillingSource(t *testing.T) {
-	input := service.AvailableChannel{
-		BillingModelSource: service.BillingModelSourceUpstream,
-	}
-	resp := availableChannelToAdminResponse(input)
-	require.Equal(t, service.BillingModelSourceUpstream, resp.BillingModelSource)
-}