feat(tools): display-disturb — deterministic display-stack disturbance generator

The stall-immunity bench needs both stall classes on demand, without a standby
TV or a monitor-tool storm: `ddc` replays the Twinkle-Tray/PowerDisplay-class
DDC/CI traffic (VCP reads, optional capabilities-string requests) through the
win32k I2C path; `modeset` re-commits the current mode with CDS_RESET — the
Level-Two modeset entry that idles the whole adapter with nothing Win32-visible
changing. Every op prints an epoch-stamped took_ms line so host.log stall
reports correlate line-for-line, and the op duration itself measures the
driver's service time per disturbance.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Cargo.toml

@@ -28,6 +28,7 @@ members = [
     "clients/session",
     "clients/windows",
     "clients/android/native",
+    "tools/display-disturb",
     "tools/latency-probe",
     "tools/loss-harness",
 ]