content: repair visitor-facing copy and briefing accessibility

Public pages no longer describe their own pipeline, case and service
labels are real accessible names, and the contact briefing writes
localized fields without empty optional lines.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/shared/case-study/case-study.html

@@ -46,6 +46,10 @@
         <li>{{ item }}</li>
       }
     </ul>
+  </section>
+
+  <section class="stack" [attr.aria-labelledby]="caseStudy().id + '-tags'">
+    <h3 [id]="caseStudy().id + '-tags'">{{ tagsLabel() }}</h3>
     <ul class="cluster tags">
       @for (tag of caseStudy().tags; track $index) {
         <li>{{ tag }}</li>