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-c7-keSetEvent/snap/ours/memory.json

@@ -0,0 +1,84 @@
+{
+  "committed_pages_total": 2594,
+  "deterministic_skip": [
+    "host_base_pointer"
+  ],
+  "engine": "ours",
+  "guest_address_space_bytes": 4294967296,
+  "heaps": [
+    {
+      "base": "0x00000000",
+      "name": "v00000000",
+      "page_size": 4096,
+      "page_state_histogram": {
+        "committed": 0
+      },
+      "size": "0x40000000"
+    },
+    {
+      "base": "0x40000000",
+      "name": "v40000000",
+      "page_size": 4096,
+      "page_state_histogram": {
+        "committed": 266
+      },
+      "size": "0x40000000"
+    },
+    {
+      "base": "0x80000000",
+      "name": "v80000000",
+      "page_size": 4096,
+      "page_state_histogram": {
+        "committed": 2336
+      },
+      "size": "0x40000000"
+    },
+    {
+      "base": "0x90000000",
+      "name": "v90000000",
+      "page_size": 4096,
+      "page_state_histogram": {
+        "committed": 0
+      },
+      "size": "0x40000000"
+    }
+  ],
+  "page_size": 4096,
+  "regions": [
+    {
+      "byte_count": 1048576,
+      "end": "0x70100000",
+      "protect": 0,
+      "section_kind": null,
+      "sha256": "30e14955ebf1352266dc2ff8067e68104607e750abb9d3b36582b8af909fcb58",
+      "start": "0x70000000"
+    },
+    {
+      "byte_count": 4096,
+      "end": "0x7ffe1000",
+      "protect": 0,
+      "section_kind": null,
+      "sha256": "ad7facb2586fc6e966c004d7d1d16b024f5805ff7cb47c7a85dabd8b48892ca7",
+      "start": "0x7ffe0000"
+    },
+    {
+      "byte_count": 4096,
+      "end": "0x7fff1000",
+      "protect": 0,
+      "section_kind": null,
+      "sha256": "e35cddaf9c210aed7505ec4cf1c599f58ac2b7ec25b0885db1ee49aba2db519a",
+      "start": "0x7fff0000"
+    },
+    {
+      "byte_count": 9568256,
+      "end": "0x82920000",
+      "protect": 0,
+      "section_kind": null,
+      "sha256": "ea8d160e9369328a5b922258a92113efb8d7ce3e1a5c12cc521e375985c91c18",
+      "start": "0x82000000"
+    }
+  ],
+  "regions_walked": [],
+  "schema_version": 1,
+  "section_contents": null
+}