Implement time off management (Issue #3)

Add full time-off lifecycle: create/edit/delete with shift conflict
detection, auto-removal from conflicting shifts with admin notification,
shift restoration on admin delete, and hard block on assigning volunteers
with approved time off to shifts.

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

internal/server/server.go

@@ -26,11 +26,12 @@ func New(db *sql.DB, jwtSecret string, staticDir string) http.Handler {
 	notificationStore := notification.NewStore(db)
 	notificationHandler := notification.NewHandler(notificationStore)
 
-	scheduleStore := schedule.NewStore(db)
-	scheduleHandler := schedule.NewHandler(scheduleStore, notificationStore)
-
 	timeoffStore := timeoff.NewStore(db)
-	timeoffHandler := timeoff.NewHandler(timeoffStore)
+
+	scheduleStore := schedule.NewStore(db)
+	scheduleHandler := schedule.NewHandler(scheduleStore, notificationStore, timeoffStore)
+
+	timeoffHandler := timeoff.NewHandler(timeoffStore, notificationStore, volunteerStore)
 
 	checkinStore := checkin.NewStore(db)
 	checkinHandler := checkin.NewHandler(checkinStore)
@@ -81,7 +82,10 @@ func New(db *sql.DB, jwtSecret string, staticDir string) http.Handler {
 			// Time off
 			r.Get("/timeoff", timeoffHandler.List)
 			r.Post("/timeoff", timeoffHandler.Create)
+			r.Put("/timeoff/{id}", timeoffHandler.Update)
+			r.Delete("/timeoff/{id}", timeoffHandler.Delete)
 			r.With(middleware.RequireAdmin).Put("/timeoff/{id}/review", timeoffHandler.Review)
+			r.With(middleware.RequireAdmin).Get("/timeoff/{id}/shifts", timeoffHandler.RemovedShifts)
 
 			// Check-in / check-out
 			r.Post("/checkin", checkinHandler.CheckIn)