docs: add StackForge release readiness docs

[rogerchappel]

Summary

• add a StackForge release-readiness guide covering the CLI-first architecture, command surface, safety model, OpenClaw workflow, and CrewCmd-later boundary
• expand the README with V1 command, safety, and release-doc entry points
• add a StackForge-specific V1 gate to the general release checklist

Verification

• Tests or checks run:
  • pnpm check
  • pnpm build
  • pnpm check:templates
  • pnpm smoke:init
• Manual review completed:
  • reviewed README and release docs for scope, consistency, and StackForge-specific release criteria

Risk Level

• Low
• Medium
• High

Notes:

• Docs-only change scoped to README and release documentation.

Rollback Plan

• revert commit b65c2a3 to remove the new release-readiness doc and restore the previous README and checklist wording

Human Decision Needed

• None
• Maintainer review
• Product/design decision
• Security/privacy review
• Other: