feat(rbac): enforce permissions on every café write endpoint

Closes the gap where the custom-role matrix was defined but unenforced — most
write endpoints only checked café membership, so the API would accept writes a
role's UI hid. Adds EnsurePermission(...) to all mutating/sensitive endpoints
across 32 controllers, mapped to the granular catalog:

- menu/inventory/coupons/customers/expenses/reservations/taxes/branches → CRUD perms
- tables/queue/kitchen-stations/print-settings → manage perms
- orders → ProcessOrders / EditOrder / VoidOrder / UpdateOrderStatus / HandlePayments,
  payment corrections → ManageFinancials
- HR → CreateStaff / ManageSchedules / ReviewLeave / View+ManageSalaries /
  ManageStaffCredentials (self-service clock-in/leave preserved)
- reports → ViewReports, export → ExportReports, audit → ViewAuditLog
- billing → ManageBilling, sms → SendSms/ManageSmsSettings, reviews → ManageReviews,
  discover/public profile → ManageDiscoverProfile, café settings → ManageCafeSettings,
  custom roles → ManageRoles

Removes legacy [Authorize(Roles=...)] attributes that would have overridden the
permission model (orders, branch-menu, pos-device, print). Manual discount/comp
have no backend endpoint yet (discounts come from coupons) — gated on the POS UI.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Meezi.API/Controllers/AuditController.cs

@@ -42,7 +42,7 @@ public class AuditController : CafeApiControllerBase
         [FromQuery] int pageSize = 50)
     {
         if (EnsureCafeAccess(cafeId, tenant) is { } denied) return denied;
-        if (EnsurePermission(tenant, Permission.ViewReports) is { } forbidden) return forbidden;
+        if (EnsurePermission(tenant, Permission.ViewAuditLog) is { } forbidden) return forbidden;
 
         if (page < 1) page = 1;
         if (pageSize < 1) pageSize = 50;