feat: enhance duty information handling with contact details and current duty view

- Added `bot_username` to settings for dynamic retrieval of the bot's username.
- Implemented `_resolve_bot_username` function to fetch the bot's username if not set, improving user experience in group chats.
- Updated `DutyWithUser` schema to include optional `phone` and `username` fields for enhanced duty information.
- Enhanced API responses to include contact details for users, ensuring better communication.
- Introduced a new current duty view in the web app, displaying active duty information along with contact options.
- Updated CSS styles for better presentation of contact information in duty cards.
- Added unit tests to verify the inclusion of contact details in API responses and the functionality of the current duty view.

duty_teller/services/group_duty_pin_service.py

@@ -85,10 +85,6 @@ def format_duty_message(duty, user, tz_name: str, lang: str = "en") -> str:
         f"🕐 {label} {time_range}",
         f"👤 {user.full_name}",
     ]
-    if user.phone:
-        lines.append(f"📞 {user.phone}")
-    if user.username:
-        lines.append(f"@{user.username}")
     return "\n".join(lines)