style: move httpx import to top-level and fix README example for MCP headers

README.md

@@ -753,15 +753,14 @@ Add MCP servers to your `config.json`:
       "filesystem": {
         "command": "npx",
         "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/dir"]
-      }
-    },
-    "urlMcpServers": {
-        "url": "https://xx.xx.xx.xx:xxxx/mcp/",
-        "headers": {
-          "Authorization": "Bearer xxxxx",
-          "X-API-Key": "xxxxxxx"
-        }
       },
+      "my-remote-mcp": {
+        "url": "https://example.com/mcp/",
+        "headers": {
+          "Authorization": "Bearer xxxxx"
+        }
+      }
+    }
   }
 }
 ```
@@ -771,7 +770,7 @@ Two transport modes are supported:
 | Mode | Config | Example |
 |------|--------|---------|
 | **Stdio** | `command` + `args` | Local process via `npx` / `uvx` |
-| **HTTP** | `url` + `option(headers)`| Remote endpoint (`https://mcp.example.com/sse`) |
+| **HTTP** | `url` + `headers` (optional) | Remote endpoint (`https://mcp.example.com/sse`) |
 
 MCP tools are automatically discovered and registered on startup. The LLM can use them alongside built-in tools — no extra configuration needed.