feat: add unit and integration tests for rental management domain

- Introduced RentPaymentCorrectionTest and RentPaymentTest to validate payment and refund logic.
- Added PhoneNumberTest to ensure proper normalization of phone numbers.
- Created TenantTest to verify attachment management and tenant referencing.
- Implemented ReplacementRentalApiJourneyIT for end-to-end testing of rental and payment workflows.
- Documented architectural decisions in ADR-0014, emphasizing strict DDD boundaries and transaction management.

frontend/src/app/app.html

@@ -1,8 +1,10 @@
-@if (session.status() === 'checking') {
+@if (session.status() === 'checking' || session.status() === 'signing-out') {
   <section class="session-state" role="status" aria-live="polite">
     <app-brand-mark class="brand-mark" />
     <mat-spinner diameter="34" />
-    <strong>Vérification de votre session…</strong>
+    <strong>{{
+      session.status() === 'signing-out' ? 'Déconnexion…' : 'Vérification de votre session…'
+    }}</strong>
   </section>
 } @else if (session.status() === 'error') {
   <section class="session-state" role="alert">