Batoi UIF 3.0.0-alpha.3

Batoi UIF 3.0.0-alpha.3 stabilizes the v3 alpha release pipeline and declaration contract.\n\n- Updates GitHub Actions to the Node 24 runtime with checkout and setup-node v6.\n- Stabilizes icon metadata declarations with a typed IconMetadataRegistry alias across macOS and Linux builds.\n- Adds regression coverage for named registry signatures.\n- Passes 417 unit/contract tests, 56 cross-browser tests, security, build, package, packed-install, provenance, integrity, and release gates.\n- Validated in an isolated Batoi RAD integration pilot covering compatibility, security, performance, query, HTTP, and release integrity checks.\n\nThis remains a prerelease pending application-owner acceptance on authenticated RAD routes and production-shaped Micro App, PWA, and governed AI/MCP integrations.