feat: analysis providers, settings UI, song search, WAV duration fix

- Multi-provider AI analysis (Anthropic, OpenAI, Ollama, Algorithmic)
- server-only guards on all provider files; client bundle fix
- /settings page with provider status, Ollama model picker, preferences
- Song search box on /analyze replacing raw MBID input (debounced, keyboard nav)
- Auto-register song via MusicBrainz on POST /api/tracks (no more 404)
- Fix WAV duration bug: last section songEnd was double-counting elapsed time
- Registry sync comment updated for self-hosted HTTPS git servers

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/layout.tsx

@@ -30,7 +30,10 @@ export default function RootLayout({
               <a href="/analyze" className="hover:text-zinc-100 transition-colors">
                 Analyze
               </a>
-              <
+              <a href="/settings" className="hover:text-zinc-100 transition-colors">
+                Settings
+              </a>
+              <a
                 href="https://github.com/your-org/clicktrack"
                 target="_blank"
                 rel="noopener noreferrer"