fix: trust X-Forwarded-Proto from Cloud Run proxy (fixes redirect_uri_mismatch)

main.py

@@ -40,6 +40,7 @@ import base64
 import json
 from functools import wraps
 from starlette.middleware.sessions import SessionMiddleware
+from uvicorn.middleware.proxy_headers import ProxyHeadersMiddleware
 from authlib.integrations.starlette_client import OAuth
 import sendgrid
 from sendgrid.helpers.mail import Mail
@@ -65,6 +66,7 @@ except Exception as e:
 
 # ── AUTH & SESSION ────────────────────────────────────────────────────────────
 # Add session middleware for storing auth state
+app.add_middleware(ProxyHeadersMiddleware, trusted_hosts="*")
 app.add_middleware(SessionMiddleware, secret_key=os.environ.get("SESSION_SECRET"))
 
 # Configure Authlib's OAuth client