Add tickets & bookings to account page

Add TicketDTO, user_tickets/user_bookings to CalendarService protocol
and SqlCalendarService implementation, plus nav links and panel
templates for the auth account sub-pages.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

contracts/dtos.py

@@ -43,6 +43,20 @@ class CalendarDTO:
     description: str | None = None
 
 
+@dataclass(frozen=True, slots=True)
+class TicketDTO:
+    id: int
+    code: str
+    state: str
+    entry_name: str
+    entry_start_at: datetime
+    entry_end_at: datetime | None = None
+    ticket_type_name: str | None = None
+    calendar_name: str | None = None
+    created_at: datetime | None = None
+    checked_in_at: datetime | None = None
+
+
 @dataclass(frozen=True, slots=True)
 class CalendarEntryDTO:
     id: int