feat: add trusted groups functionality for duty information

- Introduced a new `trusted_groups` table to store groups authorized to receive duty information.
- Implemented functions to add, remove, and check trusted groups in the database.
- Enhanced command handlers to manage trusted groups, including `/trust_group` and `/untrust_group` commands for admin users.
- Updated internationalization messages to support new commands and group status notifications.
- Added unit tests for trusted groups repository functions to ensure correct behavior and data integrity.

duty_teller/handlers/commands.py

@@ -168,6 +168,8 @@ async def help_cmd(update: Update, context: ContextTypes.DEFAULT_TYPE) -> None:
     if await is_admin_async(update.effective_user.id):
         lines.append(t(lang, "help.import_schedule"))
         lines.append(t(lang, "help.set_role"))
+        lines.append(t(lang, "help.trust_group"))
+        lines.append(t(lang, "help.untrust_group"))
     await update.message.reply_text("\n".join(lines))