commit mostly nonworking code

include/crash_handler.h

@@ -0,0 +1,13 @@
+#pragma once
+
+// Vectored AV logger: logs access violations as module+RVA (GA/UP/RR) with registers and a walk of
+// the FAULTING thread's stack. First-chance and non-intrusive.
+void InstallCrashHandler(void);
+
+// Periodically samples Unity's main thread (RIP + stack) so a stall shows up as a repeating sample.
+// See the comment block in src/debug/crash_handler.c.
+void StartHangProbe(void);
+
+// Unity's main thread id, published by the SendRequest hook the first time it runs (that hook
+// executes on the main thread). Read by the hang probe; 0 until the first request.
+extern volatile DWORD g_mainThreadId;