Deleted 8 historical STAGE*-SESSION-PROMPT.md files (all stages complete),
plus ai-session-brief.md, code-verification.md, and phase-roadmap.md
(superseded by CLAUDE.md and 254-test suite). Updated QUICK-REF.md
directory listing to reflect current docs structure.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>