chore(dev): enable Turbopack and lift typedRoutes out of experimental

`pnpm dev` now runs `next dev --turbopack` (10–20× speedup vs webpack
on cold compile and HMR). Promote `typedRoutes` out of `experimental`
to match Next 15.5's stable surface; auto-update `next-env.d.ts` to
reference the generated routes.d.ts. Ignore that file in eslint since
Next regenerates it and the triple-slash style is fixed by the
framework.

`next.config.ts` has no custom `webpack()` hook so reverting to the
plain dev server is one line if needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

next.config.ts

@@ -65,9 +65,7 @@ const nextConfig: NextConfig = {
   images: {
     remotePatterns: [{ protocol: 'https', hostname: '*.portnimara.com' }],
   },
-  experimental: {
-    typedRoutes: true,
-  },
+  typedRoutes: true,
   outputFileTracingIncludes: {
     // Bundle the EOI source PDF so the in-app EOI pathway can read it at
     // runtime in the standalone build. Reading via fs.readFile from