6cf57050228edcabc1a4a32a4c4cc598ed63aee0
Settles the undo/snapshot half (U1/U2) before implementation: - every-mutation single-step undo (supersedes destructive-only model) - hybrid whole-project snapshot (db backup API + yaml/csv copy), reconciling ADR-0006 with ADR-0015's derived-db model - persisted N=50 ring; redo discarded on new work - batch ops (replay + future) record one undo step; import excluded - --no-undo disable switch Adds the implementation plan and updates README index, requirements U1/U2, and CLAUDE.md in lockstep.
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