Prepare closed beta readiness

[Nam-Cheol]

Summary

• add closed beta program and beta test checklist docs for v1.1.0-alpha.8
• add beta bug/feedback issue forms with explicit privacy confirmation
• mark alpha/beta/rc release tags as GitHub prereleases and npm prerelease dist-tags via tested release metadata helper
• add diagnostic privacy fixture and closed beta readiness regression tests

Verification

• npm test
• npm run typecheck
• npm run check:readme-sync
• git diff --check
• node bin/orange.js --version
• node bin/orange.js env --json
• node bin/orange.js binding status --host codex --json
• node bin/orange.js activate status --host codex --json
• node bin/orange.js doctor --json
• npm pack --dry-run --cache /private/tmp/orange-hyper-npm-cache