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_app.py

@@ -254,7 +254,8 @@ def test_duties_200_with_unknown_event_type_mapped_to_duty(client):
     )
 
     def fake_get_duties(session, from_date, to_date):
-        return [(fake_duty, "User A")]
+        # get_duties returns (Duty, full_name, phone, username) tuples.
+        return [(fake_duty, "User A", "+79001234567", "user_a")]
 
     with patch("duty_teller.api.dependencies.get_duties", side_effect=fake_get_duties):
         r = client.get(
@@ -266,6 +267,8 @@ def test_duties_200_with_unknown_event_type_mapped_to_duty(client):
     assert len(data) == 1
     assert data[0]["event_type"] == "duty"
     assert data[0]["full_name"] == "User A"
+    assert data[0].get("phone") == "+79001234567"
+    assert data[0].get("username") == "user_a"
 
 
 def test_calendar_ical_team_404_invalid_token_format(client):
@@ -311,7 +314,11 @@ def test_calendar_ical_team_200_only_duty_and_description(
         end_at="2026-06-16T18:00:00Z",
         event_type="vacation",
     )
-    mock_get_duties.return_value = [(duty, "User A"), (non_duty, "User B")]
+    # get_duties returns (Duty, full_name, phone, username) tuples.
+    mock_get_duties.return_value = [
+        (duty, "User A", None, None),
+        (non_duty, "User B", None, None),
+    ]
     mock_build_team_ics.return_value = b"BEGIN:VCALENDAR\r\nPRODID:Team\r\nVEVENT\r\nDESCRIPTION:User A\r\nEND:VCALENDAR"
     token = "y" * 43
 
@@ -371,7 +378,8 @@ def test_calendar_ical_200_returns_only_that_users_duties(
         end_at="2026-06-15T18:00:00Z",
         event_type="duty",
     )
-    mock_get_duties.return_value = [(duty, "User A")]
+    # get_duties_for_user returns (Duty, full_name, phone, username) tuples.
+    mock_get_duties.return_value = [(duty, "User A", None, None)]
     mock_build_ics.return_value = (
         b"BEGIN:VCALENDAR\r\nVEVENT\r\n2026-06-15\r\nEND:VCALENDAR"
     )
@@ -415,7 +423,8 @@ def test_calendar_ical_ignores_unknown_query_params(
         end_at="2026-06-15T18:00:00Z",
         event_type="duty",
     )
-    mock_get_duties.return_value = [(duty, "User A")]
+    # get_duties_for_user returns (Duty, full_name, phone, username) tuples.
+    mock_get_duties.return_value = [(duty, "User A", None, None)]
     mock_build_ics.return_value = b"BEGIN:VCALENDAR\r\nEND:VCALENDAR"
     token = "z" * 43