fix: 添加工具注册表和 HTTP 路由，修复 MCP 工具调用 404 错误

## 问题
Product MCP 工具调用返回 404：
```
POST /tools/search_products HTTP/1.1 404 Not Found
```

## 根本原因
1. Product MCP 缺少 `/tools/{tool_name}` HTTP 路由
2. FastMCP 的 `mcp.http_app()` 默认不暴露此路由
3. Order MCP 有自定义路由处理，Product MCP 没有

## 解决方案

### 1. 添加工具注册表
**位置**: 第 32-41 行

```python
# Tool registry for HTTP access
_tools: Dict[str, Any] = {}

def register_tool(name: str):
    """Decorator to register tool in _tools dict"""
    def decorator(func):
        _tools[name] = func
        return func
    return decorator
```

### 2. 为所有工具添加注册装饰器
**修改的工具**：
- `get_product_detail`
- `recommend_products`
- `get_quote`
- `check_inventory`
- `get_categories`
- `search_products`
- `health_check`

**示例**：
```python
@register_tool("search_products")
@mcp.tool()
async def search_products(...):
```

### 3. 添加 HTTP 路由处理
**位置**: 第 352-401 行

参考 Order MCP 实现，添加：
- `/tools/{tool_name}` POST 路由
- 工具调用逻辑：`tool_obj.run(arguments)`
- 结果提取和 JSON 解析
- 错误处理（404, 400, 500）

### 4. 配置路由列表
**位置**: 第 407-415 行

```python
routes = [
    Route('/health', health_check, methods=['GET']),
    Route('/tools/{tool_name}', execute_tool, methods=['POST'])
]
```

## 测试结果

```bash
curl -X POST http://localhost:8004/tools/search_products \
  -H "Content-Type: application/json" \
  -d '{"keyword": "ring"}'
```

返回：
```json
{
  "success": true,
  "result": {
    "success": false,
    "error": "用户未登录，请先登录账户以搜索商品",
    "products": [],
    "total": 0,
    "require_login": true
  }
}
```

✅ 工具调用成功（user_token 缺失是预期行为）

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

mcp_servers/product_mcp/server.py

@@ -3,15 +3,13 @@ Product MCP Server - Product search, recommendations, and quotes
 """
 import sys
 import os
-from typing import Optional, List
+from typing import Optional, List, Dict, Any
 
 # Add shared module to path
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 from fastmcp import FastMCP
 from pydantic_settings import BaseSettings
-
-
 from pydantic import ConfigDict
 
 
@@ -31,12 +29,24 @@ mcp = FastMCP(
     "Product Service"
 )
 
+# Tool registry for HTTP access
+_tools: Dict[str, Any] = {}
+
+
+def register_tool(name: str):
+    """Decorator to register tool in _tools dict"""
+    def decorator(func):
+        _tools[name] = func
+        return func
+    return decorator
+
 
 # Hyperf client for this server
 from shared.hyperf_client import HyperfClient
 hyperf = HyperfClient(settings.hyperf_api_url, settings.hyperf_api_token)
 
 
+@register_tool("get_product_detail")
 @mcp.tool()
 async def get_product_detail(
     product_id: str
@@ -64,6 +74,7 @@ async def get_product_detail(
         }
 
 
+@register_tool("recommend_products")
 @mcp.tool()
 async def recommend_products(
     user_id: str,
@@ -112,6 +123,7 @@ async def recommend_products(
         }
 
 
+@register_tool("get_quote")
 @mcp.tool()
 async def get_quote(
     product_id: str,
@@ -171,6 +183,7 @@ async def get_quote(
         }
 
 
+@register_tool("check_inventory")
 @mcp.tool()
 async def check_inventory(
     product_ids: List[str],
@@ -204,6 +217,7 @@ async def check_inventory(
         }
 
 
+@register_tool("get_categories")
 @mcp.tool()
 async def get_categories() -> dict:
     """Get product category tree
@@ -226,6 +240,7 @@ async def get_categories() -> dict:
         }
 
 
+@register_tool("search_products")
 @mcp.tool()
 async def search_products(
     keyword: str,
@@ -317,6 +332,7 @@ async def search_products(
 
 
 # Health check endpoint
+@register_tool("health_check")
 @mcp.tool()
 async def health_check() -> dict:
     """Check server health status"""
@@ -329,17 +345,76 @@ async def health_check() -> dict:
 
 if __name__ == "__main__":
     import uvicorn
-    
-    # Create FastAPI app from MCP
-    app = mcp.http_app()
-        
-    # Add health endpoint
     from starlette.responses import JSONResponse
+    from starlette.routing import Route
+    from starlette.requests import Request
+
+    # Custom tool execution endpoint
+    async def execute_tool(request: Request):
+        """Execute an MCP tool via HTTP"""
+        tool_name = request.path_params["tool_name"]
+
+        try:
+            # Get arguments from request body
+            arguments = await request.json()
+
+            # Get tool function from registry
+            if tool_name not in _tools:
+                return JSONResponse({
+                    "success": False,
+                    "error": f"Tool '{tool_name}' not found"
+                }, status_code=404)
+
+            tool_obj = _tools[tool_name]
+
+            # Call the tool with arguments
+            # FastMCP FunctionTool.run() takes a dict of arguments
+            tool_result = await tool_obj.run(arguments)
+
+            # Extract content from ToolResult
+            # ToolResult.content is a list of TextContent objects with a 'text' attribute
+            if tool_result.content and len(tool_result.content) > 0:
+                content = tool_result.content[0].text
+                # Try to parse as JSON if possible
+                try:
+                    import json
+                    result = json.loads(content)
+                except:
+                    result = content
+            else:
+                result = None
+
+            return JSONResponse({
+                "success": True,
+                "result": result
+            })
+
+        except TypeError as e:
+            return JSONResponse({
+                "success": False,
+                "error": f"Invalid arguments: {str(e)}"
+            }, status_code=400)
+        except Exception as e:
+            return JSONResponse({
+                "success": False,
+                "error": str(e)
+            }, status_code=500)
+
+    # Health check endpoint
     async def health_check(request):
         return JSONResponse({"status": "healthy"})
 
-    # Add the route to the app
-    from starlette.routing import Route
-    app.router.routes.append(Route('/health', health_check, methods=['GET']))
+    # Create routes list
+    routes = [
+        Route('/health', health_check, methods=['GET']),
+        Route('/tools/{tool_name}', execute_tool, methods=['POST'])
+    ]
+
+    # Create app from MCP with custom routes
+    app = mcp.http_app()
+
+    # Add our custom routes to the existing app
+    for route in routes:
+        app.router.routes.append(route)
 
     uvicorn.run(app, host="0.0.0.0", port=8004)