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-keWait-timeout-encoding/digest-cold-stable-3.json

@@ -0,0 +1,6 @@
+{
+  "run": 3,
+  "total_events": 121569,
+  "det_fields_md5": "23cf4c4cbf61a577caa4118ab2308ba6",
+  "phase_b_image_canonical_sha256": "ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18"
+}