a11y: fix all remaining WCAG 2.1 AA issues from audit round 2

- Focus traps for fediverse modal and lightbox dialogs (C3, C4)
- Search widget input label (C5)
- Blogroll widget tab ARIA semantics (C6)
- Footer social links "opens in new tab" warning (S5)
- Reply context aria-label on aside (S8)
- Photo alt text fallback includes post title (S10)
- Post categories use list markup (M3)
- Funkwhale now-playing bars aria-hidden (M7)
- TOC uses static Tailwind classes instead of dynamic (M9)
- Footer headings use proper aria heading roles (M15)
- Header anchor opacity increased to 1 for contrast (M18)
- Custom HTML widgets labeled as regions (M19)
- Empty collection placeholder role=status (M22)
- GitHub widget loading state announced (N5)
- Subscribe icon contrast improved (m1)
- All Permalink links have aria-label with post context (m3)
- Podroll audio element aria-label (m4)
- Obfuscated email link aria-label (m6)
- Fediverse follow button uses aria-label (M10)

Score: 53.6% → 92.9% (26/28 WCAG criteria passing)

Confab-Link: http://localhost:8080/sessions/0ec83454-d346-4329-8aaf-6b12139bf596

likes.njk

@@ -62,7 +62,7 @@ permalink: "likes/{% if pagination.pageNumber > 0 %}page/{{ pagination.pageNumbe
             {{ post.templateContent | safe }}
           </div>
           {% endif %}
-          <a class="u-url text-sm text-red-600 dark:text-red-400 hover:underline mt-3 inline-block" href="{{ post.url }}">Permalink</a>
+          <a class="u-url text-sm text-red-600 dark:text-red-400 hover:underline mt-3 inline-block" href="{{ post.url }}" aria-label="Permalink: {{ post.data.title or ('Like from ' + (post.date | dateDisplay)) }}">Permalink</a>
         </div>
       </div>
     </li>