[lhr0909]

Prepare RespondKit 0.6.0 across npm, SwiftPM, and Maven Central. All workspace manifests and VERSION now use 0.6.0; the lockfile was refreshed and required no version changes because workspace references use links.

• Add release notes covering React Native, unread email follow-up/cancellation, greetings/email capture, native device context, R2 attachments, and the private localization compilers.
• Update the release documentation for four npm packages and document the remaining API migration/email/R2 deployment work. Merging this PR does not publish or deploy anything.
• Add a read-only npm preflight after verification and before either automated registry publication. A missing React Native package stops with bootstrap instructions; first publication uses the exact verified release artifact and account-owner npm authentication.
• Make npm publishing resumable: skip an existing version only when its registry SHA-512 matches the original verified tarball. Conflicts, missing package setup, and registry failures stop before npm publishing begins. Manual Android staging remains available.

Validation: pnpm release:check, pnpm ready, pnpm build:npm, pnpm check:npm, and pnpm pack:npm passed. The clean npm consumer checks all four 0.6.0 packages. Eight publication-planning tests and actionlint passed. Live registry preflight is read-only; React Native's first publication remains an explicit release-time step.

AI support-agent runtime APIs and localized client UI integration are not included in this release. Cloudflare configuration/deployment and npm account setup are documented requirements, not completed operations.