feat(absence) : migrate Absence domain into module (back)

LST-66 (2.3) backend. Behaviour-preserving move of the absences domain into
src/Module/Absence/. API operations, securities, routes and the 10 MCP tool
names are unchanged.

- 3 entities + 3 enums moved to Domain/{Entity,Enum}; user relations stay on
  UserInterface. 3 repositories split into Domain/Repository interfaces +
  Doctrine impls (bound in services.yaml); find() kept off interfaces
  (findById instead).
- Pure services (AbsenceDayCalculator, PublicHolidayProvider) -> Domain/Service;
  AbsenceBalanceService -> Application/Service; State (5), controllers (5),
  10 MCP tools and AccrueLeaveCommand -> Infrastructure/.
- New LeaveProfileInterface contract (Shared) exposes the HR getters used by
  AbsenceBalanceService/AccrueLeaveCommand; User implements it -> Absence no
  longer imports the concrete Core User. MCP tools/command inject
  UserRepositoryInterface (findById) instead of the concrete repository.
- Timestampable/Blamable added to AbsenceBalance and AbsencePolicy (additive
  migration: created_at/updated_at + created_by/updated_by FK ON DELETE SET
  NULL + COMMENT). AbsenceRequest untouched (already has createdAt/reviewedAt).
- AbsenceModule registered (id absence, 4 RBAC perms, not re-wired); doctrine
  mapping added; team-absences sidebar item gated by the module.

161 tests green, mapping valid, no API route regression, cs-fixer clean.

config/modules.php

@@ -7,6 +7,7 @@ declare(strict_types=1);
  * Activer/désactiver un module = ajouter/commenter sa ligne. Exposé par GET /api/modules.
  */
 
+use App\Module\Absence\AbsenceModule;
 use App\Module\Core\CoreModule;
 use App\Module\ProjectManagement\ProjectManagementModule;
 use App\Module\TimeTracking\TimeTrackingModule;
@@ -15,4 +16,5 @@ return [
     CoreModule::class,
     TimeTrackingModule::class,
     ProjectManagementModule::class,
+    AbsenceModule::class,
 ];