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-c5-NtWriteFile/snap/ours/config.json

@@ -0,0 +1,25 @@
+{
+  "build_id": "ours-phaseB",
+  "cvars": {
+    "phase_b_dump_section_content": false,
+    "phase_b_snapshot_and_exit": false,
+    "phase_b_snapshot_dir": "/home/fabi/RE - Project Sylpheed/xenia-rs/audit-runs/phase-c5-NtWriteFile/snap"
+  },
+  "deterministic_skip": [
+    "host_ns_at_snapshot",
+    "wall_clock_iso8601",
+    "build_id",
+    "iso_path",
+    "cvars.phase_b_snapshot_dir"
+  ],
+  "engine": "ours",
+  "host_ns_at_snapshot": 0,
+  "image_loaded_sha256": "ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18",
+  "iso_path": "",
+  "schema_version": 1,
+  "wall_clock_iso8601": "epoch:0",
+  "xex_entry_point": "0x824ab748",
+  "xex_header_sha256": "0000000000000000000000000000000000000000000000000000000000000000",
+  "xex_image_base": "0x82000000",
+  "xex_image_size": 9568256
+}