Move completed M4 (persist) from PLAN.md to COMPLETED.md with a decisions
note (GUID identity, Save-As copy, MarkProjectDirty, known limitation);
update CLAUDE.md repo-identity to M0-M4 complete.
Move completed M3 (offline capture spike) from PLAN.md to COMPLETED.md; close
the render-command and bank-format open questions; add capture_paths_tests to
the CLAUDE.md targets table and note M8 is dialog-free.
Move completed M2 (peaks module) from PLAN.md to COMPLETED.md; add peaks_tests
to the CLAUDE.md targets table and update the pure-core status to M0-M2 done.
Retarget README to ReaSampler and current build targets; reconcile
CLAUDE.md repo-identity + targets table to reaper_reasampler; archive
Milestone 0 from PLAN.md into new COMPLETED.md.