refactor(entitlements): migrate type-only consumers to entitlements/types (#879)

Follows the Phase 1 EntitlementProvider abstraction. Two files
imported tier types from services/LicenseService via the back-compat
re-export added in Phase 1; this PR points them at the canonical
location at entitlements/types and drops the re-export block.

Migrated:
  - backend/src/types/express.ts
  - backend/src/routes/dashboard.ts

After this PR, services/LicenseService.ts has no public type re-
exports. The remaining imports of services/LicenseService are:
  - entitlements/loadProvider.ts: runtime import of the
    LicenseService class itself, the intentional Phase 1 binding
    site.
  - __tests__/license-service-id-validation.test.ts: imports
    SENCHO_LS_* catalog constants and resolveSenchoVariantFromMeta;
    these are LemonSqueezy-implementation-specific and stay in
    services/LicenseService until Phase 2 moves the file to
    @studio-saelix/sencho-pro.

Phase 2's deletion of services/LicenseService.ts now requires zero
public-core consumer changes outside the loader and the LS-specific
test file.

Test results: 89/89 backend test files clean, 1657 passing tests, 5
pre-existing skips, plus the same pre-existing database-metrics
stress test flake under parallel load that consistently passes solo.

backend/src/routes/dashboard.ts

@@ -3,7 +3,7 @@ import { DatabaseService } from '../services/DatabaseService';
 import { CloudBackupService } from '../services/CloudBackupService';
 import { authMiddleware } from '../middleware/auth';
 import { effectiveTier, effectiveVariant } from '../middleware/tierGates';
-import type { LicenseTier, LicenseVariant } from '../services/LicenseService';
+import type { LicenseTier, LicenseVariant } from '../entitlements/types';
 
 export const dashboardRouter = Router();
 

backend/src/services/LicenseService.ts

@@ -10,14 +10,6 @@ import type {
     SeatLimits,
 } from '../entitlements/types';
 
-// Back-compat re-exports. The canonical type definitions live in
-// `entitlements/types.ts`; this re-export keeps existing imports
-// (`import type { LicenseTier } from '@/services/LicenseService'`)
-// working until consumers migrate. A follow-up PR titled
-// `refactor(entitlements): migrate type-only consumers to entitlements/types`
-// will sweep the remaining ~20 consumers; Phase 2 deletes this file.
-export type { LicenseInfo, LicenseStatus, LicenseTier, LicenseVariant, SeatLimits };
-
 // Header constants and tier/variant normalizers previously exported
 // from this file moved to `../entitlements/headers` and
 // `../entitlements/normalize` respectively, where they live in the
@@ -25,9 +17,9 @@ export type { LicenseInfo, LicenseStatus, LicenseTier, LicenseVariant, SeatLimit
 // LicenseService imports them back for internal use.
 import { isLicenseVariant, normalizeVariant } from '../entitlements/normalize';
 
-// LicenseInfo and SeatLimits live in `entitlements/types.ts` and are
-// re-exported above. The literal seat-limit table for paid variants
-// stays here because it is specific to the LemonSqueezy implementation.
+// The seat-limit table for paid variants is specific to the
+// LemonSqueezy implementation and stays in this file. Phase 2 moves it
+// to `@studio-saelix/sencho-pro` along with the rest of the file.
 const SEAT_LIMITS: Record<string, SeatLimits> = {
     skipper: { maxAdmins: 1, maxViewers: 3 },
     admiral: { maxAdmins: null, maxViewers: null },

backend/src/types/express.ts

@@ -1,5 +1,5 @@
 import type { UserRole, ApiTokenScope } from '../services/DatabaseService';
-import type { LicenseTier, LicenseVariant } from '../services/LicenseService';
+import type { LicenseTier, LicenseVariant } from '../entitlements/types';
 
 // Extend Express Request type for user and node context.
 // This file is imported for its side effects only (ambient declaration).