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/api/tracks/route.ts

@@ -1,7 +1,8 @@
 import { NextRequest, NextResponse } from "next/server";
 import { z } from "zod";
-import { getTempoMapsForSong, insertTempoMap, query } from "@/lib/db/client";
+import { getTempoMapsForSong, getSongByMbid, insertTempoMap, upsertSong } from "@/lib/db/client";
 import { validateCTP } from "@/lib/ctp/validate";
+import { lookupRecording, formatArtistCredit, mbDurationToSeconds } from "@/lib/musicbrainz/client";
 
 // ─── GET /api/tracks?mbid=<uuid> ─────────────────────────────────────────────
 
@@ -55,19 +56,33 @@ export async function POST(req: NextRequest) {
     );
   }
 
-  // Ensure the song exists
-  const { rowCount } = await query("SELECT 1 FROM songs WHERE mbid = $1", [
-    doc.metadata.mbid,
-  ]);
+  // Ensure the song exists — auto-register it if not
+  const existing = await getSongByMbid(doc.metadata.mbid);
 
-  if (!rowCount || rowCount === 0) {
-    return NextResponse.json(
-      {
-        error: "Song not found. Search for the song first to register it.",
+  if (!existing) {
+    try {
+      const rec = await lookupRecording(doc.metadata.mbid);
+      await upsertSong({
         mbid: doc.metadata.mbid,
-      },
-      { status: 404 }
-    );
+        title: rec.title,
+        artist: formatArtistCredit(rec["artist-credit"]),
+        duration_seconds: mbDurationToSeconds(rec.length),
+        acousticbrainz_bpm: null,
+        acousticbrainz_time_sig_num: null,
+        source: "musicbrainz",
+      });
+    } catch {
+      // MusicBrainz unreachable — fall back to CTP metadata
+      await upsertSong({
+        mbid: doc.metadata.mbid,
+        title: doc.metadata.title,
+        artist: doc.metadata.artist,
+        duration_seconds: doc.metadata.duration_seconds,
+        acousticbrainz_bpm: null,
+        acousticbrainz_time_sig_num: null,
+        source: "manual",
+      });
+    }
   }
 
   const map = await insertTempoMap({