style: format frontend, docs and skills with prettier; add .prettierignore

One-time prettier --write so the new format:check CI gate starts green.
.prettierignore excludes generated (api-client.ts, documentation.json),
vendored (public/cibg-huisstijl), and backend (dotnet format owns it).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/brief/ui/diagnostics-panel/diagnostics-panel.component.ts

@@ -8,17 +8,38 @@ import { Diagnostic } from '@brief/domain/placeholders';
 @Component({
   selector: 'app-diagnostics-panel',
   imports: [AlertComponent],
-  styles: [`
-    :host{display:block}
-    ul{margin:0;padding-inline-start:1.1rem;display:grid;gap:0.15rem}
-    button{background:none;border:0;padding:0;color:var(--rhc-color-foreground-link);cursor:pointer;text-align:start;text-decoration:underline}
-  `],
+  styles: [
+    `
+      :host {
+        display: block;
+      }
+      ul {
+        margin: 0;
+        padding-inline-start: 1.1rem;
+        display: grid;
+        gap: 0.15rem;
+      }
+      button {
+        background: none;
+        border: 0;
+        padding: 0;
+        color: var(--rhc-color-foreground-link);
+        cursor: pointer;
+        text-align: start;
+        text-decoration: underline;
+      }
+    `,
+  ],
   template: `
     @if (errors().length) {
       <app-alert type="error">
         <strong>{{ errorsTitle() }}</strong>
         <ul>
-          @for (d of errors(); track $index) { <li><button type="button" (click)="locate.emit(d)">{{ d.message }}</button></li> }
+          @for (d of errors(); track $index) {
+            <li>
+              <button type="button" (click)="locate.emit(d)">{{ d.message }}</button>
+            </li>
+          }
         </ul>
       </app-alert>
     }
@@ -26,7 +47,11 @@ import { Diagnostic } from '@brief/domain/placeholders';
       <app-alert type="warning">
         <strong>{{ warningsTitle() }}</strong>
         <ul>
-          @for (d of warnings(); track $index) { <li><button type="button" (click)="locate.emit(d)">{{ d.message }}</button></li> }
+          @for (d of warnings(); track $index) {
+            <li>
+              <button type="button" (click)="locate.emit(d)">{{ d.message }}</button>
+            </li>
+          }
         </ul>
       </app-alert>
     }