feat: refactor forms to use reactive forms with signals for improved state management

frontend/src/app/components/apartment-form/apartment-form.spec.ts

@@ -15,8 +15,8 @@ describe('ApartmentForm', () => {
     fixture.detectChanges();
 
     const form = fixture.componentInstance;
-    expect(form.name()).toBe('T2 Paris 15');
-    expect(form.purchasePrice()).toBe(250000);
+    expect(form.apartmentModel().name).toBe('T2 Paris 15');
+    expect(form.apartmentModel().purchasePrice).toBe(250000);
   });
 
   it('shows a validation error instead of emitting an incomplete apartment', () => {
@@ -36,10 +36,12 @@ describe('ApartmentForm', () => {
     const form = fixture.componentInstance;
     const saved = vi.fn();
     form.saved.subscribe(saved);
-    form.name.set(' T2 Paris 15 ');
-    form.address.set(' 45 rue des Entrepreneurs ');
-    form.purchasePrice.set(250000);
-    form.description.set(' Cinquième étage ');
+    form.apartmentModel.set({
+      name: ' T2 Paris 15 ',
+      address: ' 45 rue des Entrepreneurs ',
+      purchasePrice: 250000,
+      description: ' Cinquième étage ',
+    });
 
     form.save();
 
@@ -70,15 +72,18 @@ describe('ApartmentForm', () => {
     fixture.detectChanges();
     await fixture.whenStable();
     const form = fixture.componentInstance;
-    form.name.set('T2 rénové');
-    form.address.set('45 rue des Entrepreneurs');
-    form.purchasePrice.set(265000);
+    form.apartmentModel.set({
+      name: 'T2 rénové',
+      address: '45 rue des Entrepreneurs',
+      purchasePrice: 265000,
+      description: '',
+    });
     fixture.componentRef.setInput('saveError', 'Impossible d’enregistrer cet appartement.');
     fixture.detectChanges();
     await fixture.whenStable();
 
-    expect(fixture.nativeElement.querySelector('input[name=name]').value).toBe('T2 rénové');
-    expect(fixture.nativeElement.querySelector('input[name=address]').value).toBe(
+    expect(fixture.nativeElement.querySelector('input#name').value).toBe('T2 rénové');
+    expect(fixture.nativeElement.querySelector('input#address').value).toBe(
       '45 rue des Entrepreneurs',
     );
     expect(fixture.nativeElement.textContent).toContain(