handoff: VSync/event-wedge fixes + iterate 2.A–2.BC research notes

Source changes (dormant parity infra, retained from iterate 2.AI/2.AO):
- xenia-kernel/exports.rs: nt_create_event manual_reset polarity +
  related event wiring
- xenia-gpu/mmio_region.rs: D1MODE_VBLANK_VLINE_STATUS hardcode parity

Also lands the audit-runs/ analysis notes (.md/.txt/.json digests) for the
iterate 2.x VSync/0x10e8/0x1004 wedge investigation. Raw trace dumps
(.jsonl/.gz/.csv/.stdout) and agent worktrees (.claude/) are gitignored as
regenerable local artifacts — see memory + HANDOFF for the running findings.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

audit-runs/phase-c23-VdQueryVideoFlags/cold-vs-cold-result.md

@@ -0,0 +1,97 @@
+# Phase C+23 — Cold-vs-cold verification
+
+**Date:** 2026-05-26
+**Mode:** Engine modified (`vd_query_video_flags` constant return).
+Cold-vs-cold protocol: fresh `xrs-c23` cold runs vs archived canary
+jitter set.
+
+## Methodology
+
+- ours-cold jsonls: `/tmp/ours-c23-vd-cold-{1,2,3}.jsonl` (28.7 MB
+  each, 108,507 events on tid=1). Captured under
+  `XENIA_CACHE_WIPE=1` with the freshly built `xrs-c23` binary
+  (release, post-fix).
+- canary jitter set: 3 archived cold runs `canary-jitter-{1,2,3}.jsonl`
+  (4.4 / 3.5 / 3.7 GB) from
+  `xenia-canary/build-cross/bin/Windows/Debug/`. Same reference
+  jitter set used in C+20, C+21, C+22, Phase D Stage 0..4.
+- tid map: `--tid-map 6=1` (canary main thread → ours main thread).
+
+## Pre-C+23 baseline (post-C+22)
+
+```
+matched=105,138 across all 3 jitters
+first divergence: kernel.return VdQueryVideoFlags
+                  canary=3 ours=0
+                  at idx 105,138 (tid=6→1)
+```
+
+## Post-C+23 (3-jitter table)
+
+| jitter | matched | first divergence at | first-divergence kind / payload |
+|---|---|---|---|
+| 1 | **105,286** | 105,286 | `import.call VdGetCurrentDisplayGamma` (canary) vs `import.call KeAcquireSpinLockAtRaisedIrql` (ours) |
+| 2 | **105,286** | 105,286 | (same) |
+| 3 | **105,286** | 105,286 | (same) |
+
+Delta vs baseline: **+148 events** in main matched-prefix on all
+three jitters. The new first divergence (`VdGetCurrentDisplayGamma`
+vs `KeAcquireSpinLockAtRaisedIrql`) is genuine and identical across
+all three jitters.
+
+## Absorber counters (sanity)
+
+| jitter | floating_create (c/o) | floating_wait (c/o) |
+|---|---|---|
+| 1 | 0 / 0 | 1 / 0 |
+| 2 | 0 / 0 | 0 / 0 |
+| 3 | 1 / 0 | 3 / 0 |
+
+Within the expected scheduling-jitter window. Matched-prefix
+stable at 105,286 across all three.
+
+## Sister chains
+
+No sister chain regressions: the diff report lists only the main
+`tid=6 → tid=1` chain (no sister chains exercised in the new
+window). All previously matched sister chains
+(11, 32, 4, 41, 16) remain unaffected because they fire outside
+the 105,138–105,286 window.
+
+## Determinism (3 cold runs)
+
+| run | md5 | matched-prefix vs jitter-1 | ours_total |
+|---|---|---|---|
+| cold-1 | `4e2e781ff0609f3a0a08f573dee4be4e` | 105,286 | 108,507 |
+| cold-2 | `b195d82a1b61e87d6f54a2ac2b3e091b` | 105,286 | 108,507 |
+| cold-3 | `e6b94d4dc151007c924b81bbc5c9faf5` | 105,286 | 108,507 |
+
+The byte-level md5 differs (host_ns/guest_cycle wall-time jitter,
+expected) but the logical semantic state — matched-prefix,
+ours_total, first-divergence index, divergent payloads — is
+bit-identical across all 3 runs.
+
+New cold baseline digest (representative cold-1):
+**`4e2e781ff0609f3a0a08f573dee4be4e`**.
+
+## Phase B `image_canonical_sha256`
+
+Pinned hash `ea8d160e…` UNCHANGED. No XEX loader changes; only
+kernel export logic modified.
+
+## Test suite
+
+xenia-kernel: **226 PASS** (was 224 + 2 new).
+
+## Conclusion
+
+Phase C+23 advances main matched-prefix from 105,138 → 105,286
+across all three canary jitter cold runs (+148 events,
++0.0311% of canary total). The next divergence is a real
+post-VdSwap control-flow mismatch unrelated to video flags.
+
+Engine MODIFIED (~50 LOC: 1 registration edit + 6 LOC function
+body + 40 LOC tests). Diff tool UNCHANGED. Phase B
+`image_loaded_sha256` ε class boundary UNCHANGED.
+
+Tripstones 1, 2, 3, 4, 5, 6 honored.