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/proxy/passthrough.go

@@ -44,19 +44,9 @@ func parseBody(c *gin.Context) (*bodyReq, []byte, error) {
 	return br, body, nil
 }
 
-// upstreamURL 组装上游地址，智能识别用户填写的 Base URL 形式：
-//  - 完整端点(以目标资源路径结尾) → 直接使用
-//  - 已含版本前缀(如 /v1) → 只拼资源路径(/chat/completions 等)
-//  - 纯域名/地址前缀 → 拼完整路径(/v1/chat/completions 等)
-func upstreamURL(ch *store.Channel, path string) string {
-	base := strings.TrimRight(ch.BaseURL, "/")
-	if strings.HasSuffix(base, path) {
-		return base
-	}
-	if strings.HasSuffix(base, "/v1") {
-		return base + strings.TrimPrefix(path, "/v1")
-	}
-	return base + path
+// upstreamURL 组装上游地址：按协议选 base_url 再拼资源路径（见 store.Channel.UpstreamURL）。
+func upstreamURL(ch *store.Channel, proto, path string) string {
+	return ch.UpstreamURL(proto, path)
 }
 
 // doProxy 通用代理（M5）：遍历候选渠道，按需转换；可安全重试的失败自动故障转移。
@@ -103,7 +93,7 @@ func (g *Gateway) proxyOne(c *gin.Context, ch *store.Channel, plan *upstreamPlan
 
 	upBody := plan.body
 	// 直通 chat 流式：注入 stream_options.include_usage，保证末块带 usage（OpenAI 行为）
-	if stream && plan.path == "/v1/chat/completions" && plan.lineConv == nil && !bytes.Contains(upBody, []byte(`"include_usage"`)) {
+	if stream && plan.path == "/chat/completions" && plan.lineConv == nil && !bytes.Contains(upBody, []byte(`"include_usage"`)) {
 		var m map[string]any
 		if json.Unmarshal(upBody, &m) == nil {
 			m["stream_options"] = map[string]any{"include_usage": true}
@@ -115,7 +105,7 @@ func (g *Gateway) proxyOne(c *gin.Context, ch *store.Channel, plan *upstreamPlan
 
 	ctx, cancel := context.WithTimeout(c.Request.Context(), time.Duration(ch.TimeoutMS)*time.Millisecond)
 	defer cancel()
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, upstreamURL(ch, plan.path), bytes.NewReader(upBody))
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, upstreamURL(ch, plan.proto, plan.path), bytes.NewReader(upBody))
 	if err != nil {
 		return false, false, http.StatusInternalServerError, []byte("failed to build upstream request")
 	}
@@ -125,7 +115,7 @@ func (g *Gateway) proxyOne(c *gin.Context, ch *store.Channel, plan *upstreamPlan
 	if ua := c.GetHeader("User-Agent"); ua != "" {
 		req.Header.Set("User-Agent", ua)
 	}
-	if plan.path == "/v1/messages" {
+	if plan.path == "/messages" {
 		req.Header.Set("anthropic-version", "2023-06-01")
 	}
 	for _, h := range []string{"OpenAI-Organization", "OpenAI-Project", "OpenAI-Beta"} {