feat: manage tenants and leases (#4)

frontend/src/app/app.html

@@ -39,6 +39,25 @@
             (apartmentSaved)="saveApartment($event)"
           />
         }
+        @if (activeTab() === 'tenants') {
+          <app-tenants-page
+            [tenants]="tenants()"
+            (tenantSaved)="saveTenant($event)"
+            (deleteRequested)="deleteTenant($event)"
+            (attachmentUploadRequested)="uploadTenantAttachment($event)"
+            (attachmentDownloadRequested)="downloadTenantAttachment($event)"
+          />
+        }
+        @if (activeTab() === 'leases') {
+          <app-leases-page
+            [leases]="leases()"
+            [apartments]="apartments()"
+            [tenants]="tenants()"
+            (leaseSaved)="saveLease($event)"
+            (deleteRequested)="deleteLease($event)"
+            (pdfRequested)="downloadLeasePdf($event)"
+          />
+        }
         @if (activeTab() === 'settings') {
           <app-settings-page
             [username]="username"