feat(application): extract entitlement use-cases from API router layer

Move core entitlement business logic (syncEntitlement, balance reading,
year summary, set/bulk-set) into packages/application/src/use-cases/entitlement/
using the deps-injection pattern. Audit logging stays in the router support
file; authorization check for getBalance/getBalanceDetail stays in the router
layer. The router support file becomes a thin wiring adapter.

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

packages/application/src/index.ts

@@ -6,6 +6,7 @@ export { updateDemandRequirement } from "./use-cases/allocation/update-demand-re
 
 export {
   createAssignment,
+  createAssignmentFragment,
   type AssignmentWithRelations,
 } from "./use-cases/allocation/create-assignment.js";
 export { updateAssignment } from "./use-cases/allocation/update-assignment.js";
@@ -120,6 +121,54 @@ export {
   type RecomputeResourceValueScoresInput,
 } from "./use-cases/resource/index.js";
 
+export {
+  approveVacation,
+  batchApproveVacations,
+  rejectVacation,
+  batchRejectVacations,
+  cancelVacation,
+  type ApproveVacationInput,
+  type ApproveVacationResult,
+  type ApproveVacationDeps,
+  type BatchApproveVacationInput,
+  type BatchApproveVacationResult,
+  type BatchApproveVacationDeps,
+  type VacationChargeableInput,
+  type RejectVacationInput,
+  type RejectVacationResult,
+  type RejectVacationDeps,
+  type BatchRejectVacationInput,
+  type BatchRejectVacationResult,
+  type BatchRejectVacationDeps,
+  type CancelVacationInput,
+  type CancelVacationResult,
+  type CancelVacationDeps,
+} from "./use-cases/vacation/index.js";
+
+export {
+  syncEntitlement,
+  getEntitlementBalance,
+  getEntitlementBalanceDetail,
+  getEntitlementSync,
+  getEntitlementYearSummary,
+  getEntitlementYearSummaryDetail,
+  setEntitlement,
+  bulkSetEntitlements,
+  type EntitlementSnapshot,
+  type ResourceHolidayContext,
+  type SyncEntitlementDeps,
+  type ReadEntitlementBalanceDeps,
+  type EntitlementBalanceInput,
+  type EntitlementBalanceResult,
+  type EntitlementYearSummaryInput,
+  type EntitlementYearSummaryDetailInput,
+  type EntitlementYearSummaryRow,
+  type SetEntitlementInput,
+  type SetEntitlementReturn,
+  type BulkSetEntitlementsInput,
+  type BulkSetEntitlementsResult,
+} from "./use-cases/entitlement/index.js";
+
 export {
   calculateEffectiveAllocationCostCents,
   calculateEffectiveAllocationHours,