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/analyze/route.ts

@@ -1,6 +1,6 @@
 import { NextRequest, NextResponse } from "next/server";
 import { z } from "zod";
-import { generateCTPWithAI } from "@/lib/analysis/ai-ctp";
+import { getProvider, getAvailableProviders } from "@/lib/analysis/providers/registry";
 import { validateCTP } from "@/lib/ctp/validate";
 
 // ─── Request schema ───────────────────────────────────────────────────────────
@@ -12,16 +12,18 @@ const AnalyzeRequestSchema = z.object({
   artist: z.string().min(1).max(256).optional(),
   mbid: z.string().uuid().optional().nullable(),
   contributed_by: z.string().min(1).max(64).optional(),
+  provider: z.string().optional(),
+  ollamaModel: z.string().optional(),
 });
 
 /**
  * POST /api/analyze
  *
- * Accepts BPM detection results from the browser and uses Claude to generate
- * a draft CTP document for human review.
+ * Accepts BPM detection results from the browser and uses the selected provider
+ * to generate a draft CTP document for human review.
  *
  * Body (JSON):
- *   { bpm, duration, title?, artist?, mbid?, contributed_by? }
+ *   { bpm, duration, title?, artist?, mbid?, contributed_by?, provider?, ollamaModel? }
  *
  * Returns:
  *   { ctp: CTPDocument, warnings: string[] }
@@ -42,40 +44,67 @@ export async function POST(req: NextRequest) {
     );
   }
 
-  const { bpm, duration, title, artist, mbid, contributed_by } = parsed.data;
+  const { bpm, duration, title, artist, mbid, contributed_by, provider: providerId, ollamaModel } =
+    parsed.data;
 
-  if (!process.env.ANTHROPIC_API_KEY) {
+  // Validate Ollama-specific requirement
+  if (providerId === "ollama" && (!ollamaModel || ollamaModel.trim() === "")) {
     return NextResponse.json(
-      { error: "ANTHROPIC_API_KEY is not configured on this server" },
-      { status: 503 }
+      { error: "ollamaModel is required when using the Ollama provider" },
+      { status: 400 }
     );
   }
 
+  // Resolve provider
+  let provider;
+  if (providerId) {
+    try {
+      provider = await getProvider(providerId);
+    } catch (err) {
+      return NextResponse.json(
+        { error: err instanceof Error ? err.message : String(err) },
+        { status: 400 }
+      );
+    }
+  } else {
+    const available = await getAvailableProviders();
+    provider = available[0];
+    if (!provider) {
+      return NextResponse.json(
+        { error: "No analysis providers are currently available" },
+        { status: 503 }
+      );
+    }
+  }
+
+  const input = {
+    bpm,
+    duration,
+    title,
+    artist,
+    mbid: mbid ?? null,
+    contributed_by: contributed_by ?? "anonymous",
+    ollamaModel,
+  };
+
   let ctpDoc;
   try {
-    ctpDoc = await generateCTPWithAI({
-      bpm,
-      duration,
-      title,
-      artist,
-      mbid: mbid ?? null,
-      contributedBy: contributed_by ?? "anonymous",
-    });
+    ctpDoc = await provider.generateCTP(input);
   } catch (err) {
-    console.error("[analyze] AI generation failed:", err);
+    console.error(`[analyze] Provider '${provider.label}' failed:`, err);
     return NextResponse.json(
-      { error: "Failed to generate CTP document", detail: String(err) },
-      { status: 500 }
+      {
+        error: `Provider '${provider.label}' failed: ${err instanceof Error ? err.message : String(err)}`,
+      },
+      { status: 502 }
     );
   }
 
-  // Validate the AI output against the CTP schema
+  // Validate the output against the CTP schema
   const validation = validateCTP(ctpDoc);
   const warnings: string[] = [];
 
   if (!validation.success) {
-    // Rather than 500-ing, return the draft with validation warnings so the user
-    // can still see and manually correct it.
     warnings.push(...validation.errors.issues.map((i) => `${i.path.join(".")}: ${i.message}`));
   }