refactor: use simplified FastMCP app pattern with health check

src/monarch_mcp_custom/server.py

@@ -177,20 +177,14 @@ async def health_check(request):
 # --- ASGI App Setup ---
 
 
-def create_app():
-    """Create the Starlette application with MCP at /."""
+def create_app() -> Starlette:
+    """Create the Starlette application with health check and MCP."""
     mcp_app = mcp.http_app()
 
-    # FastMCP.http_app() already includes its own health check and SSE routes.
-    # By default it uses /sse for the stream and /messages for POSTs.
+    # Add health check route directly to the MCP app
+    mcp_app.add_route("/health", health_check, methods=["GET"])
 
-    return Starlette(
-        routes=[
-            Route("/health", health_check, methods=["GET"]),
-            Mount("/", app=mcp_app),
-        ],
-        lifespan=mcp_app.lifespan,
-    )
+    return mcp_app
 
 
 app = create_app()