feat(bookings): restrict management to assigned PIC or super admin

Secure API endpoints with requireBookingManager authorization check
Update confirmation page to prompt for login if unauthorized
Add safe redirect handling to login and guest middleware

server/utils/auth.ts

@@ -1,4 +1,5 @@
 import type { H3Event } from 'h3'
+import type { PublicBooking } from '~~/shared/booking'
 
 import { normalizeUsername, type UserRole } from '~~/shared/auth'
 
@@ -54,6 +55,19 @@ export async function requireRole(event: H3Event, role: UserRole) {
   return auth
 }
 
+export async function requireBookingManager(event: H3Event, booking: Pick<PublicBooking, 'personInChargeId'>) {
+  const auth = await requireAuth(event)
+
+  if (auth.user.role !== 'super_admin' && auth.user.id !== booking.personInChargeId) {
+    throw createError({
+      statusCode: 403,
+      statusMessage: 'You are not allowed to manage this booking'
+    })
+  }
+
+  return auth
+}
+
 export async function signInUser(event: H3Event, user: UserAuthRecord, remember: boolean) {
   await createUserSession(event, {
     userId: user.id,