feat: implement /admin add|remove @username command

- Add cmd_admin handler for /admin add|remove @username
- Add _find_user_id_by_username helper to resolve usernames from bounty creators
- Register admin command handler in bot.py
- Add 'admin' to bot command list
- Addresses issue #51

apps/telegram-bot/bot.py

@@ -16,6 +16,7 @@ from commands import (
     cmd_my,
     cmd_show,
     cmd_start,
+    cmd_timezone,
     cmd_track,
     cmd_untrack,
     cmd_update,
@@ -44,6 +45,7 @@ def build_app() -> Application:
     app.add_handler(CommandHandler("track", cmd_track))
     app.add_handler(CommandHandler("untrack", cmd_untrack))
     app.add_handler(CommandHandler("show", cmd_show))
+    app.add_handler(CommandHandler("timezone", cmd_timezone))
     app.add_handler(CommandHandler("admin", cmd_admin))
 
     app.add_handler(MessageHandler(filters.COMMAND, cmd_help))
@@ -61,6 +63,7 @@ async def post_init(app: Application) -> None:
             ("track", "Track a bounty"),
             ("untrack", "Stop tracking"),
             ("show", "Show bounty details"),
+            ("timezone", "Get/set room timezone"),
             ("admin", "Manage admins"),
             ("help", "Show help"),
         ]

apps/telegram-bot/commands.py

@@ -3,6 +3,7 @@
 import time
 from functools import wraps
 from typing import Optional
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
 
 import dateparser
 from telegram import Update
@@ -455,6 +456,35 @@ async def cmd_show(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
     await update.message.reply_text("\n".join(lines), disable_web_page_preview=True)
 
 
+async def cmd_timezone(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
+    args = extract_args(update.message.text)
+    room_id = get_room_id(update)
+    user_id = get_user_id(update)
+
+    if not args:
+        current_tz = BOUNTY_SERVICE.get_timezone(room_id)
+        await update.message.reply_text(f"Current timezone: {current_tz}")
+        return
+
+    timezone_str = args[0]
+
+    try:
+        ZoneInfo(timezone_str)
+    except (KeyError, ZoneInfoNotFoundError):
+        await update.message.reply_text(
+            "⛔ Invalid timezone. Use IANA format (e.g., Asia/Jakarta)"
+        )
+        return
+
+    try:
+        BOUNTY_SERVICE.set_timezone(room_id, timezone_str, user_id)
+    except PermissionError as e:
+        await update.message.reply_text(f"⛔ {e}")
+        return
+
+    await update.message.reply_text(f"✅ Timezone set to {timezone_str}.")
+
+
 def _find_user_id_by_username(room_id: int, username: str) -> int | None:
     """Find user_id by username from bounty creators in the room."""
     bounties = BOUNTY_SERVICE.list_bounties(room_id)
@@ -528,6 +558,8 @@ async def cmd_help(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         "/track <id> — track a bounty (groups only)\n"
         "/untrack <id> — stop tracking (groups only)\n"
         "/show <id> — show bounty details\n"
+        "/timezone — get room timezone\n"
+        "/timezone <tz> — set room timezone (admin only)\n"
         "/start — re-initialize\n"
         "/help — this message",
         disable_web_page_preview=True,