Adds audit_mem_watch_addr (comma-separated hex guest VAs) and
audit_mem_watch_size (1/2/4/8 bytes) to watch arbitrary guest memory
locations at runtime. Once per vblank, GraphicsSystem::MarkVblank()
reads each VA big-endian via Memory::TranslateVirtual and emits an
XELOGKERNEL "AUDIT-MEM-WATCH" line on every value change vs the prior
frame (same greppable log stream as AUDIT-HLC / AUDIT-MEM-READ).
Mechanism is poll / value-change: it captures WHEN a value changes
(vblank index) but NOT the writer guest-PC; pair with audit_jit_prolog_pc
on a suspected writer to recover the PC. Heap VAs vary per run/engine,
so they are supplied at runtime via cvar/CLI. Default empty => disabled
=> zero overhead and no emulation-behavior change.
Validated against the controller vsync "clock A" field (+0x58): the
watch fires once per change, advancing monotonically in lockstep with
vblanks. Game still boots and runs muted with the cvar unset.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
f81e90f03a