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-c12-NtQueryFullAttributesFile/cold-vs-cold-result.md

@@ -0,0 +1,21 @@
+# Cold-vs-cold result — Phase C+12 (2026-05-14)
+
+| canary_tid | ours_tid | matched | first_divergence | event-kind at divergence |
+|---|---|---|---|---|
+| 6  | 1  | **103862** | 103862 | `kernel.return NtCreateFile game:\dat\files.tbl`: canary=STATUS_OBJECT_NAME_NOT_FOUND / ours=STATUS_SUCCESS (synth-empty stub) |
+| 4  | 11 | 9      | —      | no divergence in 9 events |
+| 7  | 2  | 29     | —      | no divergence in 29 events |
+| 12 | 7  | 2      | 2      | KeWaitForSingleObject — pre-existing, not regressed |
+| 14 | 9  | 39     | 39     | XAudio init — pre-existing, not regressed |
+| 15 | 10 | 15     | —      | no divergence in 15 events |
+
+Main matched-prefix advance: **+1458 events** (102,404 → 103,862).
+
+New cold digest baseline (stable mode):
+`ad4f74ee324fdedb0bfdd4cc4c6468e9` (UNCHANGED from C+11.1 — the
+Phase C+12 fix is a pure kernel-export observation change that
+doesn't shift any of the stable counters in the digest).
+
+Phase B `image_loaded_sha256`:
+`ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18`
+(unchanged).