feat(temporal): as-of semantic recall joins the release contract — past vectors byte-exact, pinned

The time-travel recall row moves from envelope-note to contracted: vector
search at a pinned past generation serves the vectors AS THEY STOOD —
a later re-embed never leaks into an earlier pin (byte-exact), tombstones
mask, the deferred-embed pin serves the stub on the vector leg until the
landing generation (text/metadata legs unaffected — triple intelligence by
design), and beyond-head pins refuse typed. Brainy-alone leg = the
documented ephemeral at-generation materialization; the at-scale leg rides
the accelerated provider's as-of index. Registry row added (shared ID
pending the master table).

docs/path-registry.md

@@ -43,6 +43,7 @@ and what's missing, stated) · 🔴 owed (named, never silent).
 | DP6 | Single write: ack at the canonical commit; visibility committed at ack (the atomic vector update kills the remove→add dark window); maintenance NEVER holds the ack (background flush cadence — THE ACK LAW pins: a hung flush cannot block a write, a hung EMBEDDER cannot block a write). | ✅ `tests/unit/brainy/persistence-policy` + `tests/unit/hnsw/update-item-atomic` + `tests/integration/deferred-embedding` |
 | DP7 | Bulk ingest: sustained rate holds flat — per-write maintenance taxes must not grow with brain size (A4 removed caller-flush convoys; deferred embedding removes the per-write embed tax where opted). | 🟡 the decay-curve row is a pair speed-table RED GATE; brainy-alone sustained-rate run rides the same corpora |
 | DP8 | Read under write pressure: no flicker window — a row that exists is never invisible to recall, even transiently (same-vector re-index is a no-op; changed-vector swaps in place, node never leaves the index; deferred updates serve the OLD vector until the atomic swap — stale-beats-absent). | ✅ brainy leg pinned (`tests/unit/hnsw/update-item-atomic` 9/9 + `deferred-embedding` stale-beats-absent); the symmetry property suite + runtime sentinels remain the B4 program |
+| — | **As-of semantic recall** (time-travel vector search): `asOf(G).find()` serves the vectors AS THEY STOOD at G — byte-exact past vectors, tombstone masking, the deferred-embed cell honest on the vector leg, TYPED refusal beyond the head. Brainy-alone leg = ephemeral at-generation materialization (documented O(n log n at G) build, bounded); the at-scale leg rides the accelerated provider's as-of index. | ✅ `tests/integration/asof-semantic-recall` 4/4 (registry ID pending the master table's mint) |
 | — | **The lazy-open gate honors EVERY provider's not-ready report** (a not-ready metadata provider can no longer latch the silent-empty state under `disableAutoRebuild`). | ✅ `tests/unit/brainy/lazy-notready-honor` |
 
 ## MT — Maintenance (never in the door path)