Stamps the six planned post-MVP fases as the MVP2 cycle (matching the
`mvp2` branch name). Each plan file gets an "MVP2 · N/6" header. README
status + index tables group them under an MVP2 bracket. CLAUDE.md project
status reframes the planned line as MVP2 and clarifies that Fase 7+8
shipped as MVP cleanup, not MVP2.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>