docs: finalize RelayPact 0.1.1 release state

[chasechou007]

Summary

• close the documented RelayPact 0.1.1 Public Preview release state
• record the planned release date as 2026-08-13
• make the English and Chinese agent-install prompts directly reference the versioned v0.1.1 tag
• preserve the existing tag verification, trust disclosure, credential, evidence, acceptance, and terminal-action boundaries

Validation

• Node.js 20.20.2 npm run check
• publication allowlist, retained-history, and sensitive-content review
• disposable clean-clone validation
• npm pack --dry-run --json
• exact five-file security diff review: no findings

Scope

This Draft PR contains documentation-only release-state changes. It does not authorize merge, tag creation, GitHub Release creation, npm publication, or any repository-setting change.