Remove players deleted from Yodeck instead of showing them as offline

Poll loop now deletes DB rows for players no longer returned by the
Yodeck API, and Zabbix sync deletes the corresponding hosts from the
Yodeck Players group. Both actions are reflected in the activity log.

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

app/scheduler.py

@@ -14,8 +14,12 @@ def poll_yodeck():
         players = yd.get_all_screens()
         for p in players:
             db.upsert_player(p)
+        current_ids = [p['id'] for p in players]
+        removed = db.delete_players_not_in(current_ids)
         msg = f"Fetched {len(players)} players from Yodeck API"
-        db.add_log('yodeck_fetch', msg, {'count': len(players)})
+        if removed:
+            msg += f", removed {removed} deleted player(s)"
+        db.add_log('yodeck_fetch', msg, {'count': len(players), 'removed': removed})
         log.info(msg)
         # Sync host list to Zabbix after a successful fetch
         sync_to_zabbix(players, db.add_log)