fix: env parameters exception when configuring SSE or HTTP MCP server (#513)

* fix: _create_streamable_http_session() got an unexpected keyword argument 'env'

fix unit error

* update md

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

src/server/app.py

@@ -552,6 +552,7 @@ async def mcp_server_metadata(request: MCPServerMetadataRequest):
             args=request.args,
             url=request.url,
             env=request.env,
+            headers=request.headers,
             timeout_seconds=timeout,
         )
 
@@ -562,6 +563,7 @@ async def mcp_server_metadata(request: MCPServerMetadataRequest):
             args=request.args,
             url=request.url,
             env=request.env,
+            headers=request.headers,
             tools=tools,
         )