fix(docking): make workspace and lid transitions atomic

Restore the old flake's external-only workspace handoff, protect closed-lid cable removal with a verified low-level logind inhibitor, and use monitor-added as the settled audio reprobe boundary.

Verified: V2 — nix flake check --no-build; docking-ux, option-docs, and template-sot checks; KVM tools/monitor-fallback.nix lifecycle test.

V3 pending: closed-lid BenQ round 4 in agent/HARDWARE-QUEUE.md.

docs/TESTING.md

@@ -107,8 +107,11 @@ read `/var/log/nomarchy-hm-preactivate.log` on the installed system.
 
 Two full-desktop VM harnesses (softGL Hyprland, too heavy for `checks.*`)
 live next to the scripts: `tools/theme-shot.nix` (themed-desktop
-screenshots) and `tools/monitor-fallback.nix` (undock blackout rescue —
-disabled panel must re-enable when the last active output disappears).
+screenshots) and `tools/monitor-fallback.nix` (KVM display transitions:
+atomic dock handoff, internal-first undock, and low-level lid-inhibitor
+lifecycle). The latter restores the DRM output before deleting QEMU's final
+synthetic headless output; physical cable-removal timing is a V3 check because
+Hyprland's headless backend otherwise aborts in a VM-only zero-output state.
 
 ## 5. VM-specific gotchas