Force-recreate Google credentials file after snapshot restore

Modal preserves env vars across snapshot restore but not /tmp.
configure_google_credentials() short-circuits when
GOOGLE_APPLICATION_CREDENTIALS is set, so the env var survived
the snapshot while the file at that path may not, leaving Cloud
SQL Connector reads pointing at a missing credentials file.

Pop the env var before calling configure_google_credentials()
in the post-restore reset hook so the credentials file is
rewritten on every container start.

Addresses P1 review feedback on PR #1528.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hua7450

policyengine_household_api/modal_release/worker_app.py

@@ -86,10 +86,14 @@ def reset_post_snapshot_state(self) -> None:
         # captured in the snapshot hold sockets that closed at snapshot
         # time. Reset them so the first request opens fresh connections.
         #
-        # Also re-runs `configure_google_credentials()` in case Modal did
-        # not preserve `/tmp` across snapshots and the credentials file is
-        # missing on the restored filesystem.
+        # Also force-recreate the Google credentials file: Modal preserves
+        # env vars across snapshot restore, but /tmp is not guaranteed to
+        # be preserved. Without popping the env var first,
+        # configure_google_credentials() would short-circuit on the
+        # surviving GOOGLE_APPLICATION_CREDENTIALS and leave it pointing
+        # at a missing file, breaking analytics DB reconnects.
         # See: https://modal.com/docs/guide/memory-snapshot
+        os.environ.pop("GOOGLE_APPLICATION_CREDENTIALS", None)
         configure_google_credentials()
 
         from policyengine_household_api.data import analytics_setup