feat(channels): 拉模型改为勾选即绑定,启动清扫遗留模型

- fetch-models 返回 bound 标记,渠道页勾选=立即导入绑定,
  取消=解绑(无其他渠道接入时本地模型行一并删除)
- 新增 POST /channels/unbind-model
- 启动时 PurgeOrphanModels 清掉 provider 时代的无绑定模型行
- 模型管理页移除「渠道导入模型」按钮

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

backend/internal/bootstrap/app.go

@@ -115,6 +115,13 @@ func NewApp(ctx context.Context) (*App, error) {
 		channelSecret = cfg.PostgresDSN
 	}
 	channelSvc := service.NewChannelService(channelRepo, modelRepo, upClient, channelSecret)
+	// Sweep provider-era model rows: anything not bound to a channel can never
+	// be routed under the channel scheduler.
+	if n, err := channelSvc.PurgeOrphanModels(ctx); err != nil {
+		log.Printf("purge orphan models: %v", err)
+	} else if n > 0 {
+		log.Printf("purged %d unbound model(s) left over from the provider era", n)
+	}
 	v1Svc := service.NewV1Service(cfg, modelRepo, userRepo, eventRepo, channelSvc, siteRepo, cgroupRepo, concSvc, rustfsClient)
 	siteSvc := service.NewSiteService(siteRepo, cfg.AppTitle)
 	showcaseSvc := service.NewShowcaseService(showcaseRepo)

backend/internal/http/handler/channel_admin.go

@@ -106,6 +106,24 @@ func (h *ChannelAdminHandler) ImportModels(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"ok": true})
 }
 
+// UnbindModel detaches one upstream model from a channel; the local model row
+// is deleted too when no other channel still binds it.
+func (h *ChannelAdminHandler) UnbindModel(c *gin.Context) {
+	var body struct {
+		ID    string `json:"id"`
+		Model string `json:"model"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil || strings.TrimSpace(body.ID) == "" || strings.TrimSpace(body.Model) == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "id and model required"})
+		return
+	}
+	if err := h.channels.UnbindModel(c.Request.Context(), body.ID, body.Model); err != nil {
+		writeUpstreamErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}
+
 // writeUpstreamErr translates upstream-protocol errors into sensible admin
 // responses (auth → 400 with the upstream's message, temporary → 502).
 func writeUpstreamErr(c *gin.Context, err error) {

backend/internal/http/router/router.go

@@ -147,6 +147,7 @@ func New(cfg *config.Config, auth *service.AuthService, handlers Handlers) *gin.
 		authed.POST("/channels/delete", handlers.ChannelAdmin.Delete)
 		authed.POST("/channels/fetch-models", handlers.ChannelAdmin.FetchModels)
 		authed.POST("/channels/import-models", handlers.ChannelAdmin.ImportModels)
+		authed.POST("/channels/unbind-model", handlers.ChannelAdmin.UnbindModel)
 		authed.GET("/providers", handlers.AdminRead.Providers)
 		authed.GET("/images", handlers.AdminRead.Images)
 		authed.DELETE("/images", handlers.AdminRead.DeleteImage)

backend/internal/service/channel.go

@@ -205,8 +205,9 @@ type FetchModelsDto struct {
 	APIKey  string `json:"api_key"`
 }
 
-// FetchModels lists the upstream's sellable models and flags which are already
-// imported locally.
+// FetchModels lists the upstream's sellable models; when a saved channel id is
+// given, items already bound to that channel are flagged Bound so the admin UI
+// can render them as a bound/unbound toggle.
 func (s *ChannelService) FetchModels(ctx context.Context, d FetchModelsDto) ([]upstream.RemoteModel, error) {
 	base, key, err := s.resolveCreds(ctx, d.ID, d.BaseURL, d.APIKey)
 	if err != nil {
@@ -216,9 +217,75 @@ func (s *ChannelService) FetchModels(ctx context.Context, d FetchModelsDto) ([]u
 	if err != nil {
 		return nil, err
 	}
+	if strings.TrimSpace(d.ID) != "" {
+		if bound, berr := s.channels.UpstreamModelMap(ctx, d.ID); berr == nil && len(bound) > 0 {
+			set := make(map[string]struct{}, len(bound))
+			for _, upID := range bound {
+				set[upID] = struct{}{}
+			}
+			for i := range items {
+				if _, ok := set[items[i].ID]; ok {
+					items[i].Bound = true
+				}
+			}
+		}
+	}
 	return items, nil
 }
 
+// UnbindModel detaches one upstream model from a channel; when the local model
+// row ends up bound to no channel at all it is deleted too (same orphan
+// semantics as deleting a whole channel).
+func (s *ChannelService) UnbindModel(ctx context.Context, channelID, upstreamModelID string) error {
+	upID := strings.TrimSpace(upstreamModelID)
+	if upID == "" {
+		return errors.New("model id required")
+	}
+	m, err := s.channels.UpstreamModelMap(ctx, channelID)
+	if err != nil {
+		return err
+	}
+	var localID string
+	for mid, up := range m {
+		if up == upID {
+			localID = mid
+			break
+		}
+	}
+	if localID == "" {
+		return nil // not bound — idempotent
+	}
+	if err := s.channels.Unbind(ctx, channelID, localID); err != nil {
+		return err
+	}
+	if rest, _ := s.channels.ChannelIDsByModel(ctx, localID); len(rest) == 0 {
+		_, _ = s.models.Delete(ctx, localID)
+	}
+	return nil
+}
+
+// PurgeOrphanModels sweeps model_configs rows left over from the provider era:
+// an unbound model can never be routed, so any row that didn't come through a
+// channel import (provider != "channel") is deleted at startup. Channel-typed
+// orphans keep their pricing config for a later rebind.
+func (s *ChannelService) PurgeOrphanModels(ctx context.Context) (int, error) {
+	ids, err := s.channels.OrphanModelIDs(ctx)
+	if err != nil {
+		return 0, err
+	}
+	n := 0
+	for _, id := range ids {
+		m, gerr := s.models.Get(ctx, id)
+		if gerr != nil || m == nil || m.Provider == "channel" {
+			continue
+		}
+		if _, derr := s.models.Delete(ctx, id); derr == nil {
+			n++
+		}
+	}
+	return n, nil
+}
+
 // ChannelModelSpec is one model the admin ticks for import (same shape as the
 // upstream /v1/models item plus an optional local alias).
 type ChannelModelSpec struct {

backend/internal/upstream/client.go

@@ -95,6 +95,9 @@ type RemoteModel struct {
 	// Combined reference duration caps in seconds; 0 = unlimited.
 	RefVideoSeconds int64 `json:"refVideoSeconds,omitempty"`
 	RefAudioSeconds int64 `json:"refAudioSeconds,omitempty"`
+	// Bound is set by the admin fetch-models endpoint only: true when this
+	// upstream id is already bound to that channel locally.
+	Bound bool `json:"bound,omitempty"`
 }
 
 // RemoteDuration mirrors the duration spec of a vivid model item.