feat: use HTML links for admin list

Now /admin shows usernames as clickable tg://user?id= links,
same format as /show command. Uses HTML parse mode.

apps/telegram-bot/commands.py

@@ -803,11 +803,16 @@ async def cmd_admin(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         for admin_id in admins:
             username = _find_username_by_user_id(get_room_id(update), admin_id)
             if username:
-                admin_mentions.append(f"@{username}")
+                admin_mentions.append(
+                    f'<a href="tg://user?id={admin_id}">@{username}</a>'
+                )
             else:
-                admin_mentions.append(f"user#{admin_id}")
+                admin_mentions.append(
+                    f'<a href="tg://user?id={admin_id}">{admin_id}</a>'
+                )
         await update.message.reply_text(
-            f"Room Admins:\n" + "\n".join(f"- {m}" for m in admin_mentions)
+            f"Room Admins:\n" + "\n".join(f"- {m}" for m in admin_mentions),
+            parse_mode=ParseMode.HTML,
         )
         return