docs: A6.P3 #98 — record apparatus convergence + residual X-motion

The findings doc gets an evening-v2 follow-on documenting:
  - GfxObj dump infrastructure shipped (cc3afbc)
  - Harness reproduces cap-event collision normal (97fec19)
  - Residual +0.0266m X-motion divergence — the new investigation target
  - Pre-existing test suite flakiness (out of scope, tracked separately)

CLAUDE.md's "Current A6 phase" block points at the residual divergence
as the next concrete move with the test that gives <1s feedback per fix
attempt.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -842,9 +842,43 @@ cause identified.** Four commits (`fb5fba6` → `44614ab` → `0f2db62` →
 - 13 new cell fixtures cover the full 0xA9B4014X neighborhood (272 KB).
 Findings doc (canonical pickup):
 [`docs/research/2026-05-23-a6-p3-issue98-comparison-harness-findings.md`](docs/research/2026-05-23-a6-p3-issue98-comparison-harness-findings.md).
-**Next-session move: extract cottage GfxObj polygons via focused
-`ACDREAM_PROBE_BUILDING=1` capture, register as ShadowEntry in harness,
-flip first-cap test to assertion form.**
+
+**Evening v2 follow-on — apparatus convergence SHIPPED 2026-05-23 PM.**
+Two commits (`cc3afbc` → `97fec19`):
+- `cc3afbc` adds the GfxObj dump infrastructure (`ACDREAM_DUMP_GFXOBJS`)
+  mirroring the existing `ACDREAM_DUMP_CELLS` pattern, with new
+  `GfxObjDump`/`GfxObjDumpSerializer` parallel to `CellDump`. The new
+  env var triggers `PhysicsDataCache.CacheGfxObj` to write the full
+  resolved polygon table as JSON when a listed id caches. Closes the
+  gap that the existing `[resolve-bldg]` probe couldn't fill (the BSP
+  wire site that populates `LastBspHitPoly` was never wired, so the
+  probe only emitted GfxObj-level metadata, not per-poly geometry).
+- `97fec19` lands the cottage GfxObj fixture (`0x01000A2B`, 74 polygons,
+  BSP radius 13.989m matching live), the new `RegisterCottageGfxObj`
+  harness helper, and a minimum-stub landblock so
+  `TryGetLandblockContext` succeeds at the cellar XY. Harness now
+  reproduces the live `cn=(0,0,-1)` cap bit-perfect. The full per-field
+  round-trip uncovers ONE residual: live preserves +0.0266m of +X
+  motion through the cap (edge-slide along the cottage floor); harness
+  blocks all motion. Captured in
+  `LiveCompare_FirstCap_ResidualXMotionDivergence_DocumentsNextInvestigation`
+  in documents-the-bug form.
+- All 21 issue-#98-relevant tests (12 harness + 4 GfxObjDumpRoundTrip +
+  1 new PhysicsDiagnosticsTests + 4 CellDumpRoundTripTests) pass
+  deterministically in isolation.
+- Pre-existing test suite flakiness observed (8–19 failures across runs
+  of the same code, from PhysicsResolveCapture / PhysicsDiagnostics
+  statics leaking between test classes). INDEPENDENT of A6.P3 — verified
+  by stashing the cottage helper and reproducing the same flaky range.
+  Out of scope for this session; tracked as follow-up.
+
+**Next-session move:** investigate the residual +X edge-slide divergence
+in `Transition.transitional_insert` / `AdjustOffset`'s handling of a
+`cn=(0,0,-1)` head-bump. Live treats it as a Z-only constraint and
+slides the remaining XY motion along the cottage floor; harness blocks
+the entire move vector instead. The harness's
+`LiveCompare_FirstCap_ResidualXMotionDivergence_DocumentsNextInvestigation`
+test gives <1s feedback per fix attempt. ~2 hours estimate.
 Original demo scenario (Holtburg Sewer end-to-end) is unreachable: sewer
 doesn't exist on this server, and **issue #95** (portal-graph visibility
 blowup) blocks any substitute dungeon. Revised M1.5 demo split into