feat(channel): 同步 vivid 最新渠道设计 — 手动全量同步端点/并发0=不限/同名别名报错

对齐 vivid 6039423/5802749/a1f808f/cfb6d49/aba8474/b01636f:
- 新增 POST /channels/sync-models:已保存渠道手动全量同步,上游不可达/
  空清单直接报错(保存路径仍降级为告警);渠道行按钮不再弹勾选框,
  表单内对已保存渠道同样直同步,新渠道保持预览+勾选即绑定
- 渠道并发 0 = 不限制(原 0=默认5),上限放开到 int32,槽位 Lua 本就
  max=0 放行
- 别名与上游模型同名提交即报错「留空即同名」,前后端双校验
- 渠道列表去掉上游地址与模型两列(同 vivid),状态徽章悬浮显示失败原因

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

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

backend/internal/http/handler/channel_admin.go

@@ -88,6 +88,25 @@ func (h *ChannelAdminHandler) FetchModels(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"data": items})
 }
 
+// SyncModels manually re-runs the full upstream model sync on a saved channel
+// (new models bound, disappeared ones unbound, orphans deleted). Fetch
+// failures are errors here — unlike the save path which degrades to a warning.
+func (h *ChannelAdminHandler) SyncModels(c *gin.Context) {
+	var body struct {
+		ID string `json:"id"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil || strings.TrimSpace(body.ID) == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "channel id required"})
+		return
+	}
+	msg, err := h.channels.SyncModels(c.Request.Context(), body.ID)
+	if err != nil {
+		writeUpstreamErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "message": msg})
+}
+
 // ImportModels binds the ticked upstream models to the channel (creating local
 // model rows on first import).
 func (h *ChannelAdminHandler) ImportModels(c *gin.Context) {

backend/internal/http/router/router.go

@@ -146,6 +146,7 @@ func New(cfg *config.Config, auth *service.AuthService, handlers Handlers) *gin.
 		authed.POST("/channels", handlers.ChannelAdmin.Save)
 		authed.POST("/channels/delete", handlers.ChannelAdmin.Delete)
 		authed.POST("/channels/fetch-models", handlers.ChannelAdmin.FetchModels)
+		authed.POST("/channels/sync-models", handlers.ChannelAdmin.SyncModels)
 		authed.POST("/channels/import-models", handlers.ChannelAdmin.ImportModels)
 		authed.POST("/channels/unbind-model", handlers.ChannelAdmin.UnbindModel)
 		authed.GET("/providers", handlers.AdminRead.Providers)