Convert last Python fragment handlers to SX defhandlers: 100% declarative fragment API

- Add dict recursion to _convert_result for service methods returning dict[K, list[DTO]]
- New container-cards.sx: parses post_ids/slugs, calls confirmed-entries-for-posts, emits card-widget markers
- New account-page.sx: dispatches on slug for tickets/bookings panels with status pills and empty states
- Fix blog _parse_card_fragments to handle SxExpr via str() cast
- Remove events Python fragment handlers and simplify app.py to plain auto_mount

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

events/app.py

@@ -113,10 +113,7 @@ def create_app() -> "Quart":
     )
 
     from shared.sx.handlers import auto_mount_fragment_handlers
-    from bp.fragments.python_handlers import container_cards_handler, account_page_handler
-    add_fragment_handler = auto_mount_fragment_handlers(app, "events")
-    add_fragment_handler("container-cards", container_cards_handler, content_type="text/html")
-    add_fragment_handler("account-page", account_page_handler)
+    auto_mount_fragment_handlers(app, "events")
 
     app.register_blueprint(register_actions())
     app.register_blueprint(register_data())