```

feat(api): 添加万川平台模型配置获取和同步功能

- 新增 getWanchuanModelConfig 函数，按模型编码获取平台模型配置
- 新增 syncWanchuanModelToSettings 函数，从万川平台拉取模型配置并写入后端 AI 设置
- 支持按用途分多个模型编码（generic/vision/voice）分别同步配置
- 配置失败时跳过对应字段，不影响其他模型同步

feat(settings): 重构AI模型配置界面支持多模块分组

- 将AI配置按话题分析、报告生成、视觉、语音四个模块分组展示
- 每个模块独立配置接口地址、密钥和模型名称
- 添加从万川平台获取配置的按钮和同步功能
- 优化配置状态指示和错误提示信息

refactor(config): 扩展AI配置支持独立的语音视觉报告网关

- 新增 voice_base_url/voice_api_key 配置项
- 新增 vision_base_url/vision_api_key 配置项
- 新增 summary_base_url/summary_api_key 配置项
- 留空时回退到 ai_base_url/ai_api_key 兼容单网关场景

refactor(http): 统一使用共享HTTP客户端减少连接开销

- 替换各处 httpx.AsyncClient 为 shared_client
- 在 lifespan 中正确关闭共享客户端资源
- 优化 get_current_wxid 和 health 检查中的HTTP请求

refactor(ai): 按用途缓存AI客户端支持不同网关配置

- 重构 get_openai_client 支持按(base_url, api_key)缓存
- 新增 get_client_for 函数按用途获取对应客户端
- 支持语音、视觉、报告等不同用途使用独立网关和密钥
```

chatlog_fastAPI/services/media_resolver.py

@@ -10,6 +10,7 @@ from fastapi import HTTPException
 
 from config import settings
 from services.chatlog_context import get_chatlog_context
+from services.http_client import shared_client
 
 log = logging.getLogger(__name__)
 
@@ -100,25 +101,25 @@ async def diagnose_media(kind: str, key: str) -> dict:
         "chatlog_context": get_chatlog_context(),
     }
 
-    async with httpx.AsyncClient(timeout=20, trust_env=False, follow_redirects=True) as client:
-        try:
-            resp = await client.get(url)
-            content_type = resp.headers.get("content-type", "")
-            result.update(
-                {
-                    "status_code": resp.status_code,
-                    "content_type": content_type,
-                    "content_length": len(resp.content or b""),
-                    "ok": resp.status_code < 400 and bool(resp.content),
-                }
-            )
-            if resp.status_code >= 400:
-                result["error"] = _download_failure_message(kind, key, resp.status_code, resp.text[:500])
-                result["response_preview"] = resp.text[:500]
-            elif not resp.content:
-                result["error"] = "chatlog 返回了空媒体文件"
-        except Exception as exc:
-            result.update({"error": f"无法连接 chatlog 媒体接口: {exc}", "exception": str(exc)})
+    client = shared_client()
+    try:
+        resp = await client.get(url, timeout=20)
+        content_type = resp.headers.get("content-type", "")
+        result.update(
+            {
+                "status_code": resp.status_code,
+                "content_type": content_type,
+                "content_length": len(resp.content or b""),
+                "ok": resp.status_code < 400 and bool(resp.content),
+            }
+        )
+        if resp.status_code >= 400:
+            result["error"] = _download_failure_message(kind, key, resp.status_code, resp.text[:500])
+            result["response_preview"] = resp.text[:500]
+        elif not resp.content:
+            result["error"] = "chatlog 返回了空媒体文件"
+    except Exception as exc:
+        result.update({"error": f"无法连接 chatlog 媒体接口: {exc}", "exception": str(exc)})
 
     if kind == "voice":
         result["resource_db"] = _read_voice_resource_status(key)
@@ -132,30 +133,30 @@ async def resolve_media(kind: str, key: str) -> ResolvedMedia:
         raise HTTPException(400, "媒体 key 不能为空")
 
     url = _media_url(kind, key, thumb=kind in {"image", "video"})
-    async with httpx.AsyncClient(timeout=60, trust_env=False, follow_redirects=True) as client:
-        try:
-            resp = await client.get(url)
-            resp.raise_for_status()
-        except httpx.HTTPStatusError as exc:
-            diagnostics = await diagnose_media(kind, key)
-            log.warning("[media_resolver] media download failed: %s", diagnostics)
-            raise HTTPException(
-                502,
-                {
-                    "message": _download_failure_message(kind, key, exc.response.status_code, exc.response.text[:500]),
-                    "diagnostics": diagnostics,
-                },
-            )
-        except Exception as exc:
-            diagnostics = await diagnose_media(kind, key)
-            log.warning("[media_resolver] media download exception: %s", diagnostics)
-            raise HTTPException(
-                502,
-                {
-                    "message": _download_failure_message(kind, key, None, str(exc)),
-                    "diagnostics": diagnostics,
-                },
-            )
+    client = shared_client()
+    try:
+        resp = await client.get(url, timeout=60)
+        resp.raise_for_status()
+    except httpx.HTTPStatusError as exc:
+        diagnostics = await diagnose_media(kind, key)
+        log.warning("[media_resolver] media download failed: %s", diagnostics)
+        raise HTTPException(
+            502,
+            {
+                "message": _download_failure_message(kind, key, exc.response.status_code, exc.response.text[:500]),
+                "diagnostics": diagnostics,
+            },
+        )
+    except Exception as exc:
+        diagnostics = await diagnose_media(kind, key)
+        log.warning("[media_resolver] media download exception: %s", diagnostics)
+        raise HTTPException(
+            502,
+            {
+                "message": _download_failure_message(kind, key, None, str(exc)),
+                "diagnostics": diagnostics,
+            },
+        )
 
     if not resp.content:
         diagnostics = await diagnose_media(kind, key)