feat(w9e): NEW kei-replay crate — reconstruct spawn from DNA
kei-replay <dna> parses DNA, looks up ledger row, loads task.toml
from worktree, re-runs compose_prompt, recomputes body hash, reports
match/drift.
kei-replay diff <dna-1> <dna-2> flags every changed facet between
two DNAs.
6 cubes (main/lib/replay/diff/ledger_lookup), all ≤114 LOC.
Direct SQLite access in ledger_lookup.rs (kei-ledger has no lib.rs).
v4 schema-compatible (reads id/dna/worktree_path/spec_sha).
Tests: 6/6 (≥4 required): happy path, missing DNA, drift detection,
diff differing bodies, diff identical, explicit --task override.
Workspace Cargo.toml: +kei-replay member.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>