chore: remove legacy release distribution surface

[cbusillo]

Summary

• remove the legacy tag-driven Binary Release workflow and its overlay release-note/tag helpers
• simplify the active Release workflow so GitHub Releases are the only publish target
• remove deferred Homebrew generation docs/scripts and stale npm release staging
• update release policy docs and GitHub metadata to match the internal GitHub-release update-source direction

Validation

• ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release.yml"); puts "release yaml ok"'
• jq empty .github/github.json
• bash -n scripts/local/fork-health.sh
• bash -n scripts/install/install.sh
• git diff --check
• ./build-fast.sh

Closes #126.
Refs #129.
Refs #127.
Refs #128.