GET /portal/my-shifts aggregates shift assignments across all events
the logged-in user is linked to via Person records. Groups by event
then date, showing only active assignments (approved/pending_approval)
for approved/pending persons.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Backend: PortalShiftController with 4 endpoints (available-shifts,
my-shifts, claim, cancel) delegating to ShiftAssignmentService.
24 PHPUnit tests covering happy paths, auth, conflicts, and edge cases.
Frontend: claim-shifts and my-shifts pages with TanStack Query
composable, conflict detection, confirmation dialogs, and cancel flow.
Navigation and dashboard cards wired up for approved volunteers.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
