feat: LinkedIn video upload working + static file serving

- Add /public static route to serve files from /vaults/public
- Fix LinkedIn API version: 202501 → 202603 (active version)
- OpenAPI schema already included POST /api/linkedin/video
- Successfully posted Remotion video to LinkedIn

src/index.ts

@@ -35,6 +35,9 @@ app.use(cors({
 app.use(express.json());
 app.use(express.urlencoded({ extended: true }));
 
+// ── Static files (videos, assets) ──────────────────────────────────────────
+app.use('/public', express.static('/vaults/public'));
+
 // ── Config ─────────────────────────────────────────────────────────────────
 const PORT = process.env.PORT ?? 3456;
 const SERVER_URL = process.env.SERVER_URL ?? `http://localhost:${PORT}`;