Adds SPEC_DRIVEN_DEVELOPMENT.md (8-step workflow, before/after issue, persona
review example, agent-prompt example, maintenance rules, cheatsheet) and points
CLAUDE.md, COLLABORATING.md, and CONTRIBUTING.md at the new .specify/ workflow
without altering the existing cycle.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
