渠道: 模型名称映射(网关生效 + 渠道侧管理)

- 候选渠道携带 upstream_model, prepareUpstream 改写请求体 model 字段为上游名
- 新增渠道视角绑定 CRUD: GET/POST/PATCH/DELETE /admin/channels/:id/models
- 前端渠道页新增"模型映射": 列出绑定、内联改上游名、解除、添加
- rewriteModel 三种协议通用(model 均在顶层)

Co-Authored-By: Claude <noreply@anthropic.com>

server/internal/api/admin_channel_models.go

@@ -0,0 +1,122 @@
+package api
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/gin-gonic/gin"
+	"github.com/openteam/server/internal/pkg/resp"
+	"github.com/openteam/server/internal/store"
+)
+
+// AdminChannelModels GET /api/v1/admin/channels/:id/models — 渠道的模型绑定列表（含上游映射名）。
+func (h *Handler) AdminChannelModels(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var bindings []store.ChannelModelBinding
+	h.a.DB.Preload("Model").Where("channel_id = ?", id).Order("id ASC").Find(&bindings)
+	out := make([]gin.H, 0, len(bindings))
+	for _, b := range bindings {
+		out = append(out, gin.H{
+			"id":             b.ID,
+			"model_id":       b.ModelID,
+			"model_name":     b.Model.Name,
+			"upstream_model": b.UpstreamModel,
+			"weight":         b.Weight,
+		})
+	}
+	resp.OK(c, gin.H{"items": out})
+}
+
+// AdminChannelAddModel POST /api/v1/admin/channels/:id/models — 绑定模型到渠道。
+func (h *Handler) AdminChannelAddModel(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid channel id")
+		return
+	}
+	var req struct {
+		ModelName     string `json:"model_name" binding:"required"`
+		UpstreamModel string `json:"upstream_model"`
+		Weight        *int   `json:"weight"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid input")
+		return
+	}
+	var m store.Model
+	if err := h.a.DB.Where("name = ?", req.ModelName).First(&m).Error; err != nil {
+		resp.Fail(c, http.StatusNotFound, "model not found")
+		return
+	}
+	upstream := req.UpstreamModel
+	if upstream == "" {
+		upstream = m.Name
+	}
+	b := store.ChannelModelBinding{
+		ChannelID: id, ModelID: m.ID, UpstreamModel: upstream, Weight: intOr(req.Weight, 1),
+	}
+	if err := h.a.DB.Create(&b).Error; err != nil {
+		resp.Fail(c, http.StatusConflict, "binding may already exist")
+		return
+	}
+	resp.Created(c, gin.H{"id": b.ID, "model_id": m.ID, "model_name": m.Name, "upstream_model": upstream, "weight": b.Weight})
+}
+
+// AdminChannelUpdateModel PATCH /api/v1/admin/channels/:id/models/:bid — 改映射名/权重。
+func (h *Handler) AdminChannelUpdateModel(c *gin.Context) {
+	bid, err := strconv.ParseUint(c.Param("bid"), 10, 64)
+	if err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid binding id")
+		return
+	}
+	var req struct {
+		UpstreamModel *string `json:"upstream_model"`
+		Weight        *int    `json:"weight"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid input")
+		return
+	}
+	updates := map[string]any{}
+	if req.UpstreamModel != nil {
+		updates["upstream_model"] = *req.UpstreamModel
+	}
+	if req.Weight != nil {
+		updates["weight"] = *req.Weight
+	}
+	if len(updates) > 0 {
+		res := h.a.DB.Model(&store.ChannelModelBinding{}).Where("id = ?", bid).Updates(updates)
+		if res.Error != nil {
+			resp.Fail(c, http.StatusInternalServerError, "failed to update binding")
+			return
+		}
+		if res.RowsAffected == 0 {
+			resp.Fail(c, http.StatusNotFound, "binding not found")
+			return
+		}
+	}
+	resp.OK(c, gin.H{"ok": true})
+}
+
+// AdminChannelDeleteModel DELETE /api/v1/admin/channels/:id/models/:bid — 解除绑定。
+func (h *Handler) AdminChannelDeleteModel(c *gin.Context) {
+	bid, err := strconv.ParseUint(c.Param("bid"), 10, 64)
+	if err != nil {
+		resp.Fail(c, http.StatusBadRequest, "invalid binding id")
+		return
+	}
+	res := h.a.DB.Delete(&store.ChannelModelBinding{}, bid)
+	if res.Error != nil {
+		resp.Fail(c, http.StatusInternalServerError, "failed to delete binding")
+		return
+	}
+	if res.RowsAffected == 0 {
+		resp.Fail(c, http.StatusNotFound, "binding not found")
+		return
+	}
+	resp.OK(c, gin.H{"ok": true})
+}