feat: per-chat command toggle, listener name + toggle in bot tab

- Add commands_enabled field to TelegramChat (default off) with
  migration, gating command dispatch in both poller and webhook
- Show toggle switch per chat in bot tab for enabling/disabling commands
- Fix listener response to include bot name instead of just type
- Replace listener "Enabled" label + "Edit" link with toggle switch
  and crosslink to command-trackers page

frontend/src/lib/i18n/en.json

@@ -338,6 +338,8 @@
 		"chatName": "Name",
 		"chatType": "Type",
 		"chatLang": "Lang",
+		"cmds": "Cmds",
+		"commandsToggle": "Toggle command listening for this chat",
 		"chatId": "Chat ID",
 		"languageUpdated": "Chat language updated",
 		"cmdLocale": "Bot language",