fix: fix o2switch deployment build and yt-dlp Python compatibility

Turbopack requires native SWC bindings unavailable on o2switch's old
glibc, so force webpack for production builds. NODE_ENV=production on
o2switch's shell also caused npm to skip devDependencies needed at
build time (Tailwind, PostCSS), so deploy now installs with
--include=dev.

yt-dlp's standalone PyInstaller binary self-extracts to noexec /tmp
and fails to mmap its bundled shared libs there, and o2switch's system
python3 (3.6) is too old for the plain zipapp. Revert to the zipapp
and invoke it explicitly through a configurable PYTHON_BIN, set to
o2switch's newer Python 3.11 in .env.prod.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package.json

@@ -8,7 +8,7 @@
   },
   "scripts": {
     "dev": "next dev",
-    "build": "next build",
+    "build": "next build --webpack",
     "start": "node server.js",
     "test": "jest",
     "worker": "tsx worker/index.ts",