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/review-a-step1c-crowbar-v3/re-validation.md

@@ -0,0 +1,56 @@
+# Re-validation — Crowbar v3 composite progression metric
+
+**Date**: 2026-05-21
+**Method**: 3x OFF + 3x ON cold runs, 25M-instruction `check` digests.
+
+## Protocol
+
+- Binary: `target/release/xrs-crowbar3` (release build of HEAD + v3 patch).
+- Command: `xrs-crowbar3 check <ISO> -n 25000000 --gpu-thread --out <json>`.
+- OFF: no env vars set (crowbar default-off).
+- ON: `XENIA_CROWBAR_WORKERS=1 XENIA_CROWBAR_CTX_BIN=ctx-canary.bin`.
+- ISO: Sylpheed master image; no cache wipes between ours-runs (the
+  crowbar trigger is per-instr-count, deterministic).
+
+## Results
+
+| Run | instructions | swaps | draws | unique_RT | score | notes |
+|-|-:|-:|-:|-:|-:|-|
+| OFF-1 | 25,000,000 | 1 | 0 | 0 | **1** | natural halt at limit |
+| OFF-2 | 25,000,000 | 1 | 0 | 0 | **1** | natural halt at limit |
+| OFF-3 | 25,000,000 | 1 | 0 | 0 | **1** | natural halt at limit |
+| ON-1  | 20,000,167 | 1 | 0 | 0 | **1** | FAULT @ pc=0 lr=0x82506e38 r3=0xBCE25640 tid=15 |
+| ON-2  | 20,000,167 | 1 | 0 | 0 | **1** | FAULT @ pc=0 lr=0x82506e38 r3=0xBCE25640 tid=15 |
+| ON-3  | 20,000,167 | 1 | 0 | 0 | **1** | FAULT @ pc=0 lr=0x82506e38 r3=0xBCE25640 tid=15 |
+
+## Composite score (option 6 from boot-state review)
+
+```
+score = 1*swaps + 10*draws + 100*unique_render_targets
+```
+
+- OFF mean: 1.0
+- ON mean: 1.0
+- **Δ = 0**
+
+## Determinism
+
+Across 3 ON runs:
+- Fault PC, LR, CTR, r3, r4, r29, r30, r31 are bit-identical.
+- Fault cycle is bit-identical (cycle=20000167).
+- `instructions=20000167` matches across all 3 runs (deterministic
+  scheduling under the GPU thread backend).
+- `packets` varies slightly (18.6M / 18.7M / 19.1M) — expected, this
+  is the GPU thread race documented as ±2-8% jitter.
+
+## Conclusion
+
+3x replication confirms the v3 crowbar deterministically faults at
+the same dispatch site with the same register state. The
+`XENIA_CROWBAR_CTX_BIN` install path is structurally sound — it writes
+exactly the canary-captured bytes (verified via the post-install u32
+slot dump in stderr) — but the secondary-object recursion is now the
+blocker.
+
+**The hypothesis "wedge is crowbar-soluble with full ctx state +
+worker spawn" is FALSIFIED at the case-(D) recursion level.**