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.

tests/test_group_duty_pin_service.py

@@ -81,6 +81,7 @@ class TestFormatDutyMessage:
         assert result == "No duty"
 
     def test_with_duty_and_user_returns_formatted(self):
+        """Formatted message includes time range and full name only; no contact info (phone/username)."""
         duty = SimpleNamespace(
             start_at="2025-01-15T09:00:00Z",
             end_at="2025-01-15T18:00:00Z",
@@ -94,9 +95,10 @@ class TestFormatDutyMessage:
             mock_t.side_effect = lambda lang, key: "Duty" if key == "duty.label" else ""
             result = svc.format_duty_message(duty, user, "Europe/Moscow", "ru")
         assert "Иван Иванов" in result
-        assert "+79001234567" in result or "79001234567" in result
-        assert "@ivan" in result
         assert "Duty" in result
+        # Contact info is restricted to Mini App; not shown in pinned group message.
+        assert "+79001234567" not in result and "79001234567" not in result
+        assert "@ivan" not in result
 
 
 class TestGetDutyMessageText: