Align preview typography with FFmpeg output, add video/song title split, and ship OSS updates.

Separate YouTube video titles from on-video song/artist fields with Pro gating, serve curated fonts and watermark assets for 1:1 preview parity, and include billing/API/docs/deploy stack for self-hosted release.

app/api/account/api-rate-limit/route.ts

@@ -0,0 +1,20 @@
+import { NextResponse } from "next/server";
+import { getApiRateLimitStatus } from "@/lib/api-rate-limit";
+import { hasProFeatures } from "@/lib/edition";
+import { getSessionUser } from "@/lib/session";
+
+export async function GET() {
+  const user = await getSessionUser();
+  if (!user) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+  if (!hasProFeatures(user.plan)) {
+    return NextResponse.json(
+      { error: "API rate limits are available on the Pro plan only" },
+      { status: 403 },
+    );
+  }
+
+  const status = await getApiRateLimitStatus(user.id);
+  return NextResponse.json(status);
+}