feat: add comprehensive loading feedback (#18)

frontend/src/app/components/tenant-card/tenant-card.html

@@ -1,4 +1,4 @@
-<article class="tenant-card">
+<article class="tenant-card" [attr.aria-busy]="deleting() || uploading()">
   <div class="tenant-identity">
     <span class="tenant-avatar"
       >{{ tenant().firstName.charAt(0) }}{{ tenant().lastName.charAt(0) }}</span
@@ -31,11 +31,20 @@
         mat-button
         type="button"
         class="attachment-row"
+        [attr.aria-busy]="downloadingAttachmentIds().has(attachment.id)"
+        [disabled]="deleting() || downloadingAttachmentIds().has(attachment.id)"
         [attr.aria-label]="'Télécharger la pièce jointe ' + attachment.fileName"
         (click)="attachmentDownloadRequested.emit({ tenantId: tenant().id!, attachment })"
       >
-        <span aria-hidden="true">↧</span>{{ attachment.fileName }}
+        @if (downloadingAttachmentIds().has(attachment.id)) {
+          <mat-spinner diameter="16" aria-hidden="true" /> Téléchargement…
+        } @else {
+          <span aria-hidden="true">↧</span>{{ attachment.fileName }}
+        }
       </button>
+      @if (attachmentDownloadErrors()[attachment.id]) {
+        <p class="attachment-error" role="alert">{{ attachmentDownloadErrors()[attachment.id] }}</p>
+      }
     }
     @if (tenant().id) {
       @if (uploadError() || attachmentError()) {
@@ -44,24 +53,44 @@
       <label class="upload-action"
         ><input
           type="file"
+          [disabled]="uploading() || deleting()"
           [attr.aria-label]="
             'Ajouter une pièce jointe pour ' + tenant().firstName + ' ' + tenant().lastName
           "
           (change)="selectFile($event)"
         />+ Ajouter une pièce jointe <small>· 250 Mo maximum</small></label
       >
+      @if (uploading()) {
+        <div class="upload-progress" role="status" aria-live="polite">
+          <span>Envoi{{ uploadProgress() === null ? '…' : ' : ' + uploadProgress() + ' %' }}</span>
+          <mat-progress-bar
+            [mode]="uploadProgress() === null ? 'indeterminate' : 'determinate'"
+            [value]="uploadProgress() ?? 0"
+          />
+        </div>
+      }
     }
   </div>
-  <div class="card-actions">
-    <button mat-button type="button" (click)="editRequested.emit(tenant())">Modifier</button>
+  @if (deleteError()) {
+    <p class="attachment-error" role="alert">{{ deleteError() }}</p>
+  }
+  <div class="card-actions" aria-live="polite">
+    <button mat-button type="button" [disabled]="deleting()" (click)="editRequested.emit(tenant())">
+      Modifier
+    </button>
     @if (tenant().id) {
       <button
         mat-button
         type="button"
         class="danger-action"
+        [disabled]="deleting()"
         (click)="deleteRequested.emit(tenant().id!)"
       >
-        Supprimer
+        @if (deleting()) {
+          <mat-spinner diameter="16" aria-hidden="true" /> Suppression…
+        } @else {
+          Supprimer
+        }
       </button>
     }
   </div>