docs-frontmatter-cleanup: the 11 invalid last_updated frontmatter scalars quoted — double-quote convention applied uniformly (one escaped quote in phase-0.md), annotation prose verbatim; PyYAML sweep over docs/**/*.md + tasks/*.md reports 0 failures, taskgraph validate green (79 tasks); task status -> completed with Notes (recorded sweep command, date-scalar caveat) + Summary

docs/architecture/engine-mem.md

@@ -1,13 +1,13 @@
 ---
 status: stable
-last_updated: 2026-10-10 (the wave-6 review gate passed: the
+last_updated: "2026-10-10 (the wave-6 review gate passed: the
 conformance read clean — three edge-domain fixes landed inline (the
 stream cursor read's `i64::MAX` overflow, `trim_to`'s horizon
 endpoint, the scheduler register-time interval overflow now rejecting
 with `InvalidSpec` like the SQLite register) plus scaffold-residue
 cleanup; the third column's 25-row set green under the current-thread
 flavor; the wasm32 gate + feature subset verified; the rider's arms
-verified)
+verified)"
 ---
 
 # Mem engine