渠道: 分协议 Base URL + 模型抽屉/远程拉取/操作图标

- 渠道支持分协议 base_url(chat/responses/messages 各一), 网关按协议选 base 直通
  (如智谱三种格式不同 base, 一个渠道即可), UpstreamURL 按 proto 拼接
- 渠道模型改为下方抽屉: 当前绑定列表(内联改上游/解除)、从接口拉取(remote 预览+勾选添加)、手动添加
- 新增 /channels/:id/models/remote 预览接口; 操作按钮加 Phosphor 图标
- 修复 formats jsonb 更新未序列化问题; 手机端渠道卡片化

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

server/internal/api/admin_channel_models.go

@@ -1,14 +1,67 @@
 package api
 
 import (
+	"encoding/json"
 	"net/http"
 	"strconv"
+	"strings"
+	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/openteam/server/internal/pkg/resp"
 	"github.com/openteam/server/internal/store"
 )
 
+// AdminChannelRemoteModels GET /api/v1/admin/channels/:id/models/remote
+// 拉取渠道接口的模型列表（仅预览，不绑定）。
+func (h *Handler) AdminChannelRemoteModels(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 ch store.Channel
+	if err := h.a.DB.First(&ch, id).Error; err != nil {
+		resp.Fail(c, http.StatusNotFound, "channel not found")
+		return
+	}
+	key, err := h.a.Enc.Decrypt(ch.APIKeyEnc)
+	if err != nil {
+		resp.Fail(c, http.StatusInternalServerError, "failed to decrypt channel key")
+		return
+	}
+	client := &http.Client{Timeout: 15 * time.Second}
+	req, _ := http.NewRequest(http.MethodGet, ch.UpstreamURL("", "/models"), nil)
+	req.Header.Set("Authorization", "Bearer "+key)
+	req.Header.Set("Accept", "application/json")
+	resp2, err := client.Do(req)
+	if err != nil {
+		resp.Fail(c, http.StatusBadGateway, "failed to reach channel: "+err.Error())
+		return
+	}
+	defer resp2.Body.Close()
+	if resp2.StatusCode != http.StatusOK {
+		resp.Fail(c, http.StatusBadGateway, "channel returned http "+strconv.Itoa(resp2.StatusCode))
+		return
+	}
+	var list struct {
+		Data []struct {
+			ID string `json:"id"`
+		} `json:"data"`
+	}
+	if err := json.NewDecoder(resp2.Body).Decode(&list); err != nil {
+		resp.Fail(c, http.StatusBadGateway, "failed to parse model list")
+		return
+	}
+	items := make([]string, 0, len(list.Data))
+	for _, m := range list.Data {
+		if strings.TrimSpace(m.ID) != "" {
+			items = append(items, strings.TrimSpace(m.ID))
+		}
+	}
+	resp.OK(c, gin.H{"items": items})
+}
+
 // 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)