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>

lib/ctp/render.ts

@@ -149,7 +149,10 @@ function calculateBeats(doc: CTPDocument): Beat[] {
         }
       } else {
         // Last section: generate beats until we exceed duration_seconds
-        const songEnd = cursor + doc.metadata.duration_seconds;
+        const countInSeconds = doc.count_in.enabled
+          ? (doc.count_in.bars * firstNumerator * 60) / firstBpm
+          : 0;
+        const songEnd = countInSeconds + doc.metadata.duration_seconds;
         // Estimate bars remaining
         const approxBarsRemaining = Math.ceil(
           (doc.metadata.duration_seconds / 60) * section.bpm / numerator + 2