Add react-flight-server-fb package for Meta's internal bundler

[imdreamrunner]

Summary

• Adds a new react-flight-server-fb package providing RSC Flight bindings for Meta's internal bundler stack
• Unlike webpack/turbopack integrations, this uses no manifest. Module metadata is self-contained in ClientReference objects and sent over the wire as-is
• Registers dom-browser-fb and dom-node-fb host configs for Rollup builds targeting FB_WWW_DEV and FB_WWW_PROD

Key design differences from other bundler

• No build-time manifest
• Module IDs use Haste module names (e.g. "MyComponent"), with named exports encoded as "Module#export", rather than file paths resolved through a manifest
• Client-side loading uses Bootloader.handlePayload() + JSResource().load()
• resolveClientReferenceMetadata and resolveClientReference are pass-throughs

How did you test this change?

E2E integration test is set up on Meta's internal system.