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/manifest.json

@@ -0,0 +1,11 @@
+{
+  "engine": "ours",
+  "files": {
+    "config.json": "656a2df4f35d20fd6d8caa0b7145ee232aa3325cef27d31c550ca8aae9e748f2",
+    "cpu_state.json": "4e6df54ca1939d08854f3a52b49ed2c5ee0823d63cdecad8a7395203dac5443a",
+    "kernel.json": "b64ea3a6c14f1b0aaadc6de8adbb894edf636a813120d08028ca096e1d06bacc",
+    "memory.json": "b96ae4daebfbdd314e574492c1e162f532fa4f89ff5c0d7c6c29743797089cf1",
+    "vfs.json": "97bb2bda57266d8e0dd1da13309eab5ece43130ef378a0b682917d299e9dc4e1"
+  },
+  "schema_version": 1
+}