Gateway startup leaks aiohttp.ClientSession (and other partial-init
resources) when an adapter's connect() returns False or raises. The
adapter is never added to self.adapters, so the shutdown path at
gateway/run.py:2426 never calls disconnect() on it — Python GC later
logs 'Unclosed client session' at process exit.
Seen on 2026-04-18 18:08:16 during a double --replace takeover cycle:
one of the partial-init sessions survived past shutdown and emitted
the warning right before status=75/TEMPFAIL.
Fix:
- New GatewayRunner._safe_adapter_disconnect() helper — calls
adapter.disconnect() and swallows any exception. Used on error paths.
- Connect loop calls it in both failure branches: success=False and
except Exception.
- Adapter disconnect() implementations are already expected to be
idempotent and tolerate partial-init state (they all guard on
self._http_session / self._bridge_process before touching them).
Tests: tests/gateway/test_safe_adapter_disconnect.py — 3 cases verify
the helper forwards to disconnect, swallows exceptions, and tolerates
platform=None.
