feat: add profiling middleware and update README for performance profiling

app/middleware/profiler.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from fastapi import Request
+from pyinstrument import Profiler
+from starlette.middleware.base import (
+    BaseHTTPMiddleware,
+    RequestResponseEndpoint,
+)
+from starlette.responses import HTMLResponse, Response
+
+
+class ProfilingMiddleware(BaseHTTPMiddleware):
+    async def dispatch(
+        self, request: Request, call_next: RequestResponseEndpoint
+    ) -> Response:
+        if request.query_params.get("pyprofile") == "true":
+            profiler = Profiler(interval=0.001, async_mode="enabled")
+            profiler.start()
+
+            await call_next(request)
+
+            profiler.stop()
+            return HTMLResponse(
+                profiler.output_html(),
+                headers={"Content-Disposition": "attachment; filename=profile.html"},
+            )
+
+        return await call_next(request)