Fix Docker build by adding missing files and tsx dependency

- Add scripts/ directory to build stage for sync-assets.mjs
- Add index.html to build stage for Vite entry point
- Move tsx to production dependencies for server runtime
- Copy src/ and tsconfig.json to production stage for tsx

These changes enable the Docker build to complete successfully and
allow the server to run TypeScript files directly in production.

Dockerfile

@@ -16,6 +16,8 @@ COPY vite.config.ts ./
 COPY tailwind.config.js ./
 COPY postcss.config.js ./
 COPY eslint.config.js ./
+COPY index.html ./
+COPY scripts ./scripts
 COPY resources ./resources
 COPY proprietary ./proprietary
 COPY src ./src