fix: use group timezone in bounty list and show command

1. format_bounty now accepts timezone_str parameter
2. Calculate hours/days remaining using group's timezone
3. Format dates using group's timezone (not server local time)
4. Updated cmd_bounty, cmd_my, cmd_show to pass timezone

apps/telegram-bot/commands.py

@@ -144,7 +144,9 @@ def parse_args(
     return text, link, due_date_ts, clear_link, clear_date
 
 
-def format_bounty(b, show_id: bool = True, slice_length: int = 0) -> str:
+def format_bounty(
+    b, show_id: bool = True, slice_length: int = 0, timezone_str: str = "UTC"
+) -> str:
     parts = []
     if show_id:
         parts.append(f"[#{b.id}]")
@@ -156,12 +158,20 @@ def format_bounty(b, show_id: bool = True, slice_length: int = 0) -> str:
     if b.link:
         parts.append(f"🔗 {b.link}")
     if b.due_date_ts:
-        now = int(time.time())
-        seconds_left = b.due_date_ts - now
+        try:
+            tz = ZoneInfo(timezone_str)
+        except (KeyError, ZoneInfoNotFoundError):
+            tz = ZoneInfo("UTC")
+
+        now_utc = int(time.time())
+        dt_now = datetime.now(tz)
+        dt_due = datetime.fromtimestamp(b.due_date_ts, tz=tz)
+
+        seconds_left = int((dt_due - dt_now).total_seconds())
         hours_left = seconds_left // 3600
         days_left = seconds_left // 86400
 
-        due_str = time.strftime("%d %b %Y %H:%M", time.localtime(b.due_date_ts))
+        due_str = dt_due.strftime("%d %b %Y %H:%M")
 
         if seconds_left < 0:
             parts.append(f"⏰ {due_str} (OVERDUE)")
@@ -232,6 +242,7 @@ def get_room_id(update: Update) -> int:
 async def cmd_bounty(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
     room_id = get_room_id(update)
     user_id = get_user_id(update)
+    timezone_str = BOUNTY_SERVICE.get_timezone(room_id)
     args = extract_args(update.message.text)
 
     show_all = "all" in args
@@ -282,7 +293,11 @@ async def cmd_bounty(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         slice_length = 0
 
     for b in displayed_bounties:
-        lines.append(format_bounty(b, show_id=True, slice_length=slice_length))
+        lines.append(
+            format_bounty(
+                b, show_id=True, slice_length=slice_length, timezone_str=timezone_str
+            )
+        )
 
     keyboard = [[InlineKeyboardButton("🗑️ Delete", callback_data=f"del_msg:{user_id}")]]
     reply_markup = InlineKeyboardMarkup(keyboard)
@@ -302,6 +317,8 @@ async def cmd_my(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         room_id = get_room_id(update)
         bounties = BOUNTY_SERVICE.list_bounties(room_id)
 
+    timezone_str = BOUNTY_SERVICE.get_timezone(room_id)
+
     if not bounties:
         msg = (
             "You are not tracking any bounties."
@@ -311,7 +328,9 @@ async def cmd_my(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         await update.message.reply_text(msg)
         return
 
-    lines = [format_bounty(b, show_id=True) for b in bounties]
+    lines = [
+        format_bounty(b, show_id=True, timezone_str=timezone_str) for b in bounties
+    ]
     await update.message.reply_text("\n".join(lines), disable_web_page_preview=True)
 
 
@@ -609,7 +628,12 @@ async def cmd_show(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         await update.message.reply_text("Bounty not found.")
         return
 
-    timezone = BOUNTY_SERVICE.get_timezone(room_id)
+    timezone_str = BOUNTY_SERVICE.get_timezone(room_id)
+
+    try:
+        tz = ZoneInfo(timezone_str)
+    except (KeyError, ZoneInfoNotFoundError):
+        tz = ZoneInfo("UTC")
 
     lines = []
 
@@ -620,13 +644,15 @@ async def cmd_show(update: Update, ctx: ContextTypes.DEFAULT_TYPE) -> None:
         lines.append(f"🔗 {bounty.link}")
 
     if bounty.due_date_ts:
-        due_str = time.strftime("%d %B %Y %H:%M", time.localtime(bounty.due_date_ts))
-        lines.append(f"📅 {due_str} ({timezone})")
+        dt_due = datetime.fromtimestamp(bounty.due_date_ts, tz=tz)
+        due_str = dt_due.strftime("%d %B %Y %H:%M")
+        lines.append(f"📅 {due_str} ({timezone_str})")
 
     username = bounty.created_by_username or f"user#{bounty.created_by_user_id}"
     lines.append(f"👤 @{username}")
 
-    created_str = time.strftime("%Y-%m-%d %H:%M", time.localtime(bounty.created_at))
+    dt_created = datetime.fromtimestamp(bounty.created_at, tz=tz)
+    created_str = dt_created.strftime("%Y-%m-%d %H:%M")
     lines.append(f"📌 Created: {created_str}")
 
     await update.message.reply_text("\n".join(lines), disable_web_page_preview=True)