fix: upsert evotor_connection by user_id fallback to prevent duplicate insert

When a connection row exists for the user but with a different/null
evotor_user_id, the lookup by evotor_user_id alone missed it and tried
to INSERT, hitting the unique constraint on user_id. Now looks up by
either evotor_user_id or user_id, and always syncs both fields on update.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/routes/evotor_webhooks.py

@@ -63,13 +63,18 @@ def _upsert_evotor_connection(
     """Create or update an evotor_connections row; always regenerates api_token."""
     api_token = secrets.token_urlsafe(32)
     conn = db.query(EvotorConnection).filter(
-        EvotorConnection.evotor_user_id == evotor_user_id
+        or_(
+            EvotorConnection.evotor_user_id == evotor_user_id,
+            EvotorConnection.user_id == user_id,
+        )
     ).first()
     now = datetime.now(timezone.utc).replace(tzinfo=None)
     if conn:
         conn.api_token = api_token
         if user_id is not None:
             conn.user_id = user_id
+        if evotor_user_id:
+            conn.evotor_user_id = evotor_user_id
         if access_token:
             conn.access_token = access_token
         conn.updated_at = now