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>

services/stubs.py

@@ -13,6 +13,7 @@ from shared.contracts.dtos import (
     PostDTO,
     CalendarDTO,
     CalendarEntryDTO,
+    TicketDTO,
     MarketPlaceDTO,
     ProductDTO,
     CartItemDTO,
@@ -82,6 +83,16 @@ class StubCalendarService:
     ) -> list[CalendarEntryDTO]:
         return []
 
+    async def user_tickets(
+        self, session: AsyncSession, *, user_id: int,
+    ) -> list[TicketDTO]:
+        return []
+
+    async def user_bookings(
+        self, session: AsyncSession, *, user_id: int,
+    ) -> list[CalendarEntryDTO]:
+        return []
+
 
 class StubMarketService:
     async def marketplaces_for_container(