test(docking): prove the keyboard-restore path; the reload clobber is real

The last unproven half of bec826b, and it needed a keyboard that stays behind
when the dock leaves. The dev box's by-tech hangs off the BenQ's own hub, so
it always walked away with the cable — a Logitech K400 with its receiver in
the laptop is the real case, and Bernardo happened to plug one in.

Both halves measured on hardware (dev box, 2026-07-14):

  - PRIMARY: across a real unplug + the fixed transition, the K400 kept its
    remembered `us`. Panel back, layout intact.
  - CONTROL: a bare `hyprctl reload` with no restore took the same board from
    `us` to the session's `gb`.

The control matters more than the pass. That reload clobbers runtime
`device[<name>]:kb_layout` was an inference from the mechanism when
restore_keyboards was written — reasonable, but unmeasured, and this session
has already shown what unmeasured reasoning about this watcher is worth.
It holds: without that call the undock's escalation would have silently
broken the layout of every keyboard that outlives the cable, trading a black
panel for a keyboard that types the wrong characters at the password prompt.

Verified V2 again after the comment/doc edits: nix flake check --no-build,
checks.docking-ux, shellcheck clean.

Round 8 now asks only for what is still open: relogin (the watcher calls the
transition by baked store path, so exec-once means it runs the old build
until then) and repetition — 5+ unplugs, one with the lid shut.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/HARDWARE-QUEUE.md

@@ -49,19 +49,21 @@ the **T14s** (webcam case).
       The transition now escalates to `reload` when the keyword proves inert,
       re-asserts the rule, and restores per-device keyboard layouts (a reload
       drops runtime `device[…]:kb_layout` keywords).
-      **Already proven on hardware:** one real unplug, invoking the fixed
-      `nomarchy-display-transition undock eDP-1` directly with the watcher
-      paused — panel on and workspaces 1–3 home in 1.8s, journal
-      `keyword=inert escalate=reload` → `enable=via-reload` → `result=ok`.
+      **Already proven on hardware** (2026-07-14, two real unplugs invoking
+      the fixed `nomarchy-display-transition undock eDP-1` directly with the
+      watcher paused): panel on and workspaces 1–3 home in 1.8s, journal
+      `keyword=inert escalate=reload` → `enable=via-reload` → `result=ok`; and
+      the keyboard-restore path with a Logitech K400 whose receiver is in the
+      laptop — it kept its remembered `us` across the undock, while a control
+      `hyprctl reload` with no restore dropped it to the session's `gb`
+      (so `restore_keyboards` is load-bearing, not insurance).
       **What is NOT proven, and is this round:** the *watcher-driven* path
       (the running watcher calls the transition by baked store path, so it
       only picks the fix up at relogin — the round-5 trap), and repetition.
       **Re-check:** relogin (mandatory — see below), dock, then unplug the
-      cable **at least five times**, plus once with the lid shut and once
-      while an external keyboard is plugged into the *laptop* (not the dock's
-      hub) — that last one is the only check on the keyboard-restore path.
-      **Pass:** the panel comes back every time with workspaces intact, the
-      external keyboard keeps its remembered layout, and `journalctl --user
+      cable **at least five times**, plus once with the lid shut.
+      **Pass:** the panel comes back every time with workspaces intact, and
+      `journalctl --user
       -t nomarchy-display-transition -t nomarchy-display-watch --since
       '-10 min'` shows `result=ok` for each undock with **no**
       `result=enable-failed`. `keyword=inert escalate=reload` on every undock