Optimize npm package size by downloading platform-specific binaries in postinstall (~100MB -> ~20MB)

What feature would you like to see?

The current npm package bundles binaries for all platforms, but only one platform-specific binary is needed per installation.

Current Behavior

• All platform binaries are included via install_native_deps.sh in stage_release.sh
• Runtime platform detection in bin/codex.js selects the correct binary

Proposed Solution
Replace the current approach with a postinstall script that downloads only the required binary based on the platform:

• Postinstall script detects platform and downloads appropriate binary from GitHub Releases
• Binary to be served from github releases instead of npm registry
• Update stage_release.sh to publish lightweight package

Are you interested in implementing this feature?

Yes

Additional information

Binary will be served from github releases instead of npm registry after this - so need to check how versioning is setup github release packages