bd-first-memory-migrationlisted

# bd-first-memory-migration (Codex twin) Make `bd` the single source of truth for agent memory: salvage the keepers, derive the caches, garbage-collect and retire the rest. Three phases, gated between destructive steps. ## Phases 1. **Audit** (read-only) — inventory every memory layer, classify keepers vs junk, and produce the Gate A manifest + reversibility plan. Nothing is written. ⛔ Gate A before any mutation. 2. **Migrate** (writes to bd only) — import keepers into bd as typed memories with provenance, stand up decay-ranked recall, unify the write path so every runtime routes to bd, and regenerate the thin read-only memory-index cache. 3. **GC / Retire** (destructive) — utility scoring, scheduled GC + dedup to a cold archive, contradiction/supersede detection, and the hard-retire of dead stores with disk reclaim. ⛔ Gate B (rollback test green) + ⛔ Gate C (human go/no-go on a live box). ## Guardrails - Idempotent, reversible, backup-aware; every destructive step offers a dry run. - Pace bd writes — bulk salvage unpaced can overwhelm a memory-capped server. - bd-canonical (not br); authored content is archived, never hard-deleted. ## Instructions Load and follow the skill instructions from the sibling `SKILL.md` file for this skill. Then read local files in `references/` when needed.