feat(embedding): deferred-embed markers become log records — the sidecar recovery path is deleted

The private recovery discipline, applied to its own machinery: pending-
embed markers stop being sidecar files and become first-class log records
riding the write's OWN commit fact — embed.pending lands in the same
atomic append as its after-image (a marker can never be orphaned from its
write, or vice versa; in durable-at-ack mode it shares the write's
covering fsync — zero extra syncs), and the worker's landing commit rides
embed.landed with the inline vector. Crash recovery is now a FOLD of the
log (pending without a matching landed = recovered), skipped wholesale on
brains with no v2 history; the one-time legacy bridge folds existing
sidecar files in, migrates them as one fact, and deletes them —
idempotent under a crash mid-bridge. No code path writes the sidecar
again.

Plus the ENTITY-TRUTH digest law, found by this train's own pins:
canonical vector wrappers denormalize HNSW residue (connections + the
randomly-assigned node level) that the log deliberately does not carry —
the verification oracle digested it and would have reported false
state-differs on ~any nonzero-level node (a ~15% flake in the cutover pin
was the symptom). Both sides of every oracle comparison now normalize to
entity truth (nounEntityTruth); index residue has its own rebuild path
and is not entity state.

Pins: embed-markers-in-log 5/5 (same-generation marker, landed+fold-to-
zero, crash recovery via the log with the sidecar prefix EMPTY on disk,
legacy bridge, VFS hung-embedder ack) · deferred-embedding 5/5 unchanged
(the contract outlived its mechanism) · kill-matrix 11/11 · cutover 5/5
×10 runs (flake dead) · unit 2031/2031.

src/db/logAuthority.ts

@@ -92,6 +92,27 @@ export async function readLogAuthority(
   return { authority: 'tree' }
 }
 
+/**
+ * Normalize a canonical noun record to its ENTITY TRUTH before diffing:
+ * the canonical vector-file wrapper denormalizes derived index residue
+ * (`connections` — HNSW graph edges; `level` — the node's random skip-list
+ * level) that the generation log deliberately does NOT carry (projections
+ * own their own rebuild paths). Digesting the residue would report false
+ * `state-differs` on ~any brain whose HNSW assigned a nonzero level. Both
+ * sides of every oracle comparison pass through this normalizer.
+ */
+export function nounEntityTruth(record: {
+  metadata: unknown
+  vector: unknown
+}): { metadata: unknown; vector: unknown } {
+  const v = record.vector
+  if (v && typeof v === 'object' && !Array.isArray(v)) {
+    const { connections: _c, level: _l, ...entity } = v as Record<string, unknown>
+    return { metadata: record.metadata, vector: entity }
+  }
+  return { metadata: record.metadata, vector: v }
+}
+
 /**
  * Stable content hash of a stored record for diffing — key-sorted JSON so
  * property order can never fake a divergence.