docs: POC #1 ran — SQLite posture verdict Arm A, findings + register note

docs/research/phase-0.md

@@ -600,6 +600,12 @@ land in `docs/research/` here. Named per the OQ each feeds:
 |---|---|---|---|
 | 1 | SQLite engine posture: honker-core-on-rusqlite vs honker-extension-over-sqlx (async seam, watcher, transactional contract, packaging, interop) | [poc-sqlite-posture-spec.md](poc-sqlite-posture-spec.md) | OQ-ST-03, OQ-ST-04, OQ-ST-06 |
 
+POC #1 **ran (2026-10-04)** — verdict Arm A (honker-core on our
+rusqlite), findings in
+[poc-sqlite-posture-findings.md](poc-sqlite-posture-findings.md);
+OQ-ST-03's SQLite half and OQ-ST-04's SQLite wake side now have
+measured input.
+
 ## Phase 0 plan
 
 Iteration expected; this register grows as research rounds land.