feat: implement /timezone command to get/set room timezone

Re-implement the timezone command that was reverted.

- Add cmd_timezone function with get/set functionality
- Validate timezone using zoneinfo (IANA format)
- Admin-only permission via service layer
- Update help text and bot command list
- Fix indentation bug in cmd_add (duplicate lines)

Fixes #53

apps/telegram-bot/bot.py

@@ -8,7 +8,6 @@ from telegram.ext import Application, CommandHandler, MessageHandler, filters
 
 from commands import (
     cmd_add,
-    cmd_admin,
     cmd_bounty,
     cmd_delete,
     cmd_edit,
@@ -16,6 +15,7 @@ from commands import (
     cmd_my,
     cmd_show,
     cmd_start,
+    cmd_timezone,
     cmd_track,
     cmd_untrack,
     cmd_update,
@@ -44,7 +44,7 @@ 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("admin", cmd_admin))
+    app.add_handler(CommandHandler("timezone", cmd_timezone))
 
     app.add_handler(MessageHandler(filters.COMMAND, cmd_help))
 
@@ -61,7 +61,7 @@ async def post_init(app: Application) -> None:
             ("track", "Track a bounty"),
             ("untrack", "Stop tracking"),
             ("show", "Show bounty details"),
-            ("admin", "Manage admins"),
+            ("timezone", "Get/set room timezone"),
             ("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
@@ -455,63 +456,33 @@ async def cmd_show(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
     await update.message.reply_text("\n".join(lines), disable_web_page_preview=True)
 
 
-def _find_user_id_by_username(room_id: int, username: str) -> int | None:
+async def cmd_timezone(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
-    """Find user_id by username from bounty creators in the room."""
-    bounties = BOUNTY_SERVICE.list_bounties(room_id)
-    for bounty in bounties:
-        if (
-            bounty.created_by_username
-            and bounty.created_by_username.lower() == username.lower()
-        ):
-            return bounty.created_by_user_id
-    return None
-
-
-async def cmd_admin(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
     args = extract_args(update.message.text)
-    if not args or args[0] not in ("add", "remove"):
+    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(
-            "Usage:\n"
+            "⛔ Invalid timezone. Use IANA format (e.g., Asia/Jakarta)"
-            "/admin add @username — add admin\n"
-            "/admin remove @username — remove admin"
         )
         return
 
-    subcommand = args[0]
-
-    if len(args) < 2:
-        await update.message.reply_text(f"Usage: /admin {subcommand} @username")
-        return
-
-    raw_username = args[1]
-    if not raw_username.startswith("@"):
-        await update.message.reply_text(f"Usage: /admin {subcommand} @username")
-        return
-
-    username = raw_username[1:]
-
-    user_id = get_user_id(update)
-    room_id = get_room_id(update)
-
-    if not BOUNTY_SERVICE.is_admin(room_id, user_id):
-        await update.message.reply_text("⛔ Only admins can perform this action.")
-        return
-
-    target_user_id = _find_user_id_by_username(room_id, username)
-
-    if target_user_id is None:
-        await update.message.reply_text(f"⛔ User @{username} not found.")
-        return
-
     try:
-        if subcommand == "add":
+        BOUNTY_SERVICE.set_timezone(room_id, timezone_str, user_id)
-            BOUNTY_SERVICE.add_admin(room_id, target_user_id, user_id)
-            await update.message.reply_text(f"✅ @{username} is now an admin.")
-        elif subcommand == "remove":
-            BOUNTY_SERVICE.remove_admin(room_id, target_user_id, user_id)
-            await update.message.reply_text(f"✅ @{username} is no longer an admin.")
     except PermissionError as e:
         await update.message.reply_text(f"⛔ {e}")
+        return
+
+    await update.message.reply_text(f"✅ Timezone set to {timezone_str}.")
 
 
 async def cmd_help(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
@@ -528,6 +499,8 @@ 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,