feat: initial Transmute app — universal client-side file converter

Full-stack client-side file converter with Next.js 15 static export.
Supports images (Canvas API), documents (mammoth/pdf-lib/jspdf),
audio/video (ffmpeg.wasm), and data formats (papaparse/yaml/xml).
Dark industrial UI with Space Grotesk + JetBrains Mono, animated
drop zone, glassmorphism file cards, progress rings, and ZIP downloads.
Zero server dependencies — files never leave the browser.

vercel.json

@@ -0,0 +1,11 @@
+{
+  "headers": [
+    {
+      "source": "/(.*)",
+      "headers": [
+        { "key": "Cross-Origin-Embedder-Policy", "value": "require-corp" },
+        { "key": "Cross-Origin-Opener-Policy", "value": "same-origin" }
+      ]
+    }
+  ]
+}