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-c22-rtl-enter-leave-control-flow/re-validation.md

@@ -0,0 +1,80 @@
+# Phase C+22 re-validation (2026-05-18)
+
+## Protocol followed
+
+Cold-vs-cold per reading-error #31 + #32 + #33 + the new #34.
+
+1. ✓ Backed up both canary cache locations
+   (`xenia-canary/build-cross/bin/Windows/Debug/cache/` and
+   `~/.local/share/Xenia/cache/`) to tarballs.
+2. ✓ Wiped both canary caches + ours's
+   (`~/.local/share/xenia-rs/cache/`).
+3. ✓ Cold-ran ours (50M instructions) against the `.iso`
+   path — NOT the loose `default.xex` (per new
+   reading-error #34).
+4. ✓ Cold-ran canary (90s timeout) against the `.iso` path
+   with `--mute=true`.
+5. ✓ Truncated canary log to first 250k events per tid
+   (keeping ALL tids, NOT only tid=6 — needed for the C+18 /
+   C+21 cross-tid shared-global heuristic).
+6. ✓ Ran `diff_events.py` with full tid map
+   `6=1,7=2,4=11,12=7,14=9,15=10`.
+7. ✓ Restored both canary cache backups.
+
+## Determinism check
+
+- ours-cold byte-identical to C+19 archive (`audit-runs/
+  phase-c19-NtDuplicateObject-handle-create/ours-cold.jsonl`):
+  121,569 events match post-normalization (host_ns and
+  guest_cycle excluded). Reproduces deterministically.
+- No new engine source changes, so digest unchanged. Phase B
+  `image_loaded_sha256 = ea8d160e9369328a5b922258a92113efb8d
+  7ce3e1a5c12cc521e375985c91c18` preserved.
+
+## Gate matrix (escalation mode)
+
+| gate                                        | result            |
+|---------------------------------------------|-------------------|
+| Engine source unchanged                     | PASS              |
+| Diff-tool source unchanged                  | PASS              |
+| Phase A schema version 1 unchanged          | PASS              |
+| ours-cold byte-equivalent to C+19 archive   | PASS (121,569 ev) |
+| Main matched-prefix preserved at C+21       | PASS (104,607)    |
+| Sister chains preserved (11/32/3/41/16)     | PASS              |
+| C+21 absorber engaged (validation)          | PASS (2/0 wait)   |
+| C+18 absorber engaged (validation)          | PASS (1/0 create) |
+| Phase B image hash preserved                | PASS              |
+| Canary caches restored                      | PASS              |
+| Reading-error #34 documented + reproducible | PASS              |
+| Tests count (no change)                     | 204 (unchanged)   |
+
+## What changed in the diff-tool report compared to C+21 baseline
+
+NOTHING substantive. The numbers are identical:
+
+| chain                       | C+21 (jitter-1) | C+22 (fresh c22) |
+|-----------------------------|-----------------|------------------|
+| tid=6→1                     | 104,607         | 104,607          |
+| tid=4→11                    | 11              | 11               |
+| tid=7→2                     | 32              | 32               |
+| tid=12→7                    | 3               | 3                |
+| tid=14→9                    | 41              | 41               |
+| tid=15→10                   | 16              | 16               |
+| main floating_create (c/o)  | 0 / 0           | 1 / 0            |
+| main floating_wait (c/o)    | 1 / 0           | 2 / 0            |
+
+The floating counts vary across canary cold samples (different
+host-scheduler interleavings emit the wait.begin in different
+counts and at different indices) but the matched-prefix is
+constant — this is the C+21 fix working as designed.
+
+## Outcome
+
+- C+22 = ESCALATION (no engine change).
+- Cold-vs-cold environment is healthy and reproducible.
+- C+21 absorber works correctly under varying contention.
+- Reading-error #34 added as a methodology guard for future
+  cold-vs-cold runs.
+- Next-target list updated: C+23 = D-NEW-2 (independent
+  ε-class), C+24 = D-NEW-3 (XAudio), parallel scheduler-
+  determinism track.