feat(directory) : migrate Client into Directory module (back)

LST-58 (2.4), part 1/2 — Client move. Prospect + repertoire front are pending
the product spec and will be added on this branch afterward.

- Client entity moved to src/Module/Directory/Domain/Entity; repository split
  into Domain/Repository/ClientRepositoryInterface + Doctrine impl (bound in
  services.yaml). 5 client MCP tools moved to Infrastructure/Mcp/Tool, now
  injecting the interface.
- resolve_target_entities ClientInterface repointed to Directory\Client;
  Directory mapping added; DirectoryModule registered (id directory, 2 RBAC
  perms). Client.projects relation now uses ProjectInterface -> Directory no
  longer depends on ProjectManagement.
- ProjectManagement Create/UpdateProjectTool inject Directory's
  ClientRepositoryInterface; Serializer and fixtures repointed.
- Garde-fous: #[Auditable] + Timestampable/Blamable on Client (additive
  migration: created_at/updated_at + created_by/updated_by FK ON DELETE SET
  NULL + COMMENT).

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

config/packages/doctrine.yaml

@@ -25,7 +25,7 @@ doctrine:
             App\Shared\Domain\Contract\ProjectInterface: App\Module\ProjectManagement\Domain\Entity\Project
             App\Shared\Domain\Contract\TaskInterface: App\Module\ProjectManagement\Domain\Entity\Task
             App\Shared\Domain\Contract\TaskTagInterface: App\Module\ProjectManagement\Domain\Entity\TaskTag
-            App\Shared\Domain\Contract\ClientInterface: App\Entity\Client
+            App\Shared\Domain\Contract\ClientInterface: App\Module\Directory\Domain\Entity\Client
         mappings:
             App:
                 type: attribute
@@ -53,6 +53,11 @@ doctrine:
                 is_bundle: false
                 dir: '%kernel.project_dir%/src/Module/Absence/Domain/Entity'
                 prefix: 'App\Module\Absence\Domain\Entity'
+            Directory:
+                type: attribute
+                is_bundle: false
+                dir: '%kernel.project_dir%/src/Module/Directory/Domain/Entity'
+                prefix: 'App\Module\Directory\Domain\Entity'
         controller_resolver:
             auto_mapping: false