fix(display): #142 — dock mode is an intent, and survives a rebuild

Every rebuild while docked re-lit the panel and threw a workspace onto
it. Not forgetfulness: a rebuild PERFORMS an undock. Dock mode lived only
in the compositor (`keyword monitor <internal>, disable`, nothing written
down), the config's only monitor line is the catch-all
`monitor=,preferred,auto,1`, and rewriting the config makes Hyprland
reload it — re-enabling every output. Our own undock path already uses
`hyprctl reload` as exactly that hammer (hardware-proven 2026-07-14).

The watcher could not rescue it: reconcile diffs `monitors all`, which
lists disabled outputs, so the connected set is identical across the flip
— structurally blind, the blind spot of rounds 4-5's "the output set is
the truth".

So the intent is recorded where every other setting lives —
settings.display.dockMode, in-flake, menu-writable — written at the one
choke point both menu and watcher pass through (transition: dock → true,
undock → false, `enable` of an internal → false, because "Screen on" IS
leaving dock mode and must not be undone a second later). The watcher
re-asserts it as a tick invariant rather than an event reaction, which is
what makes the reload case work; auto_dock was already idempotent, so it
costs one `hyprctl monitors` per tick.

The trap avoided: baking the disable into the config would survive a
reload and hand a user with no external a zero-output session at login —
the #100/#127 brick. The config cannot know what is plugged in, so it
keeps defaulting to "everything on" and the re-assert is gated on an
external being present.

Verified: 9/9 gates unit-tested by driving the REAL generated function
against stubs (incl. no-external → never re-dock, profile active → yield,
already-docked → no churn), plus the state write/read round-trip on a
throwaway checkout so the live flake was untouched. V3 queued — needs a
relogin, the watcher is exec-once.

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

agent/HARDWARE-QUEUE.md

@@ -509,6 +509,22 @@ Everything else below stays open; order is convenience, not a gate.
       active and PPD switching governors; opt-ins: ROCm (`rocminfo`, a GPU
       PyTorch/Ollama smoke) and the XDNA NPU driver loading.
 - [ ] **Fingerprint** — `fprintd-enroll` + (opt-in PAM) login/sudo.
+- [ ] **#142 dock mode survives a rebuild** — **relogin first** (the watcher is
+      `exec-once`; `nomarchy-home` alone leaves the old one running and you
+      would be testing nothing — round 6's lesson). Then, docked: run
+      `nomarchy-home`. Pass = the laptop panel stays off, no workspace lands on
+      it, no menu trip; `journalctl --user -t nomarchy-display-watch` shows
+      `dock-intent=true panel=eDP-1 state=re-enabled action=re-dock` (a rebuild
+      re-lights the panel and the watcher takes it back within ~1s, so a brief
+      flicker is expected — the panel staying *up* is the failure).
+      Then the three gates that must NOT fire, since this code can disable a
+      panel: (a) Menu ▸ Display ▸ **Screen on** → the panel stays on (intent
+      cleared; if it snaps off again within a second, that is the bug);
+      (b) **undock** → panel returns and stays; (c) boot/relogin **undocked**
+      with `settings.display.dockMode` still `true` in state.json → panel stays
+      on (no external ⇒ never re-dock). (c) is the one that matters: it is the
+      #127 brick if it is wrong. Gates are unit-tested against stubs, but only
+      hardware proves the wiring.
 - [ ] **#138 dock audio does not break a running browser** — the plug event
       itself is the only thing V2 could not do (the tool was driven by hand;
       Hyprland calls the same entry point). **Relogin first** — the watcher is