fix: Fail-closed pinned resolver, close session on HA stop, drop dead workflow step

- _PinnedResolver raises on unpinned hosts instead of falling back to
  live DNS: nothing legitimate resolves other hosts on a pinned session
  (redirects are off), so fail closed
- dedicated session is also closed on EVENT_HOMEASSISTANT_CLOSE: core
  stop does not unload entries, and the raw ClientSession has no HA
  auto-cleanup, which left 'Unclosed client session' logs at shutdown
- hassfest.yaml: remove the version-print step, hassfest runs inside
  the action's docker image and is never on the runner PATH

custom_components/ha_text_ai/__init__.py

@@ -16,7 +16,7 @@ import asyncio
 import voluptuous as vol
 
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import CONF_API_KEY, CONF_NAME
+from homeassistant.const import CONF_API_KEY, CONF_NAME, EVENT_HOMEASSISTANT_CLOSE
 from homeassistant.core import HomeAssistant, ServiceCall, SupportsResponse
 from homeassistant.exceptions import ConfigEntryNotReady, HomeAssistantError
 from homeassistant.helpers import config_validation as cv
@@ -379,6 +379,19 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         # Register update listener for options changes
         entry.async_on_unload(entry.add_update_listener(async_update_options))
 
+        # HA Core stop does not unload entries, so close the dedicated
+        # session on the CLOSE event too; unload removes this listener
+        # and closes the session via APIClient.shutdown() instead.
+        async def _async_close_session_on_stop(_event) -> None:
+            if not session.closed:
+                await session.close()
+
+        entry.async_on_unload(
+            hass.bus.async_listen_once(
+                EVENT_HOMEASSISTANT_CLOSE, _async_close_session_on_stop
+            )
+        )
+
         _LOGGER.debug("Setup completed for %s", instance_name)
 
         return True