feat: graceful no-JS fallback and noscript handling

- Add <noscript><style> in base.njk that unhides x-cloak/x-show content,
  hides FAB and tab buttons when JS is disabled (content stacks instead)
- Add noscript message on search page with links to blog/categories
- Add noscript banner on interactions page explaining inbound tab needs JS

interactions.njk

@@ -8,6 +8,12 @@ permalink: /interactions/
   <p class="text-surface-600 dark:text-surface-400">Activity across the IndieWeb - both my engagement and responses to my content.</p>
 </div>
 
+<noscript>
+  <div class="p-4 bg-amber-50 dark:bg-amber-900/20 border border-amber-200 dark:border-amber-800 rounded-lg mb-6">
+    <p class="text-amber-800 dark:text-amber-200 text-sm">The inbound webmentions tab requires JavaScript to load data from the API. Enable JavaScript for the full interactive experience. Outbound interactions are shown below.</p>
+  </div>
+</noscript>
+
 {# Tab navigation for Outbound/Inbound #}
 <div x-data="interactionsApp()" x-init="init()">
   {# Tab buttons #}