docs(agent): file #127 — docked idle blackout, no wake, undock no panel

Bernardo 2026-07-15: docked idle → black screens; external KB/mouse did
not wake; unplugging the external did not restore eDP; Caps Lock still
worked. Captures the "session crash" as a seat brick. HARDWARE-QUEUE
repro + journal steps for the next controlled run.

agent/BACKLOG.md

@@ -72,6 +72,35 @@ buttons in the installer (VM gum screens under Boreal look legible —
 artifacts in `/tmp/nomarchy-v2-swap-93/`). Needs Bernardo's screenshot or
 an Acer repro to pin the actual widget before fixing.
 
+### 127. `[blocked:hw]` Docked idle: black screens, no wake, undock does not restore panel
+
+Bernardo 2026-07-15 (AMD dev box, docked): left the laptop docked; after a
+few minutes of idle it appeared to "sleep". Then:
+
+1. External keyboard/mouse did **not** wake any display.
+2. Unplugging the external monitor did **not** turn the laptop panel back
+   on (dock mode has eDP disabled — undock *should* re-enable it).
+3. The machine was still alive: Caps Lock LED toggled on the keyboard.
+
+This also killed a long agent session (looked like a "crash" from the
+outside). Separate from awake undock recovery (HARDWARE-QUEUE round 8):
+the failure is **idle while docked**, then no path back to a usable panel.
+
+**Likely shape (code-side, unconfirmed on the incident):** on AC, hypridle
+does **not** call `systemctl suspend` (`onAc || suspend` — only battery
+suspends at 15 min). Idle path is lock @5 min + `dpms off` @10 min
+(`modules/home/idle.nix`). Caps Lock working fits **DPMS/lock blackout**
+better than deep S3. Dock mode has already disabled eDP; recovery then
+needs either (a) input → hypridle `on-resume` / `dpms on` on the external,
+or (b) undock → `nomarchy-display-transition undock` re-enabling the
+panel. Both failed. `after_sleep_cmd` only does `hyprctl dispatch dpms on`
+and never re-enables a disabled internal.
+
+**Pass:** docked on AC, idle past lock + DPMS; external KB/mouse restores
+the external; if the external is unplugged while black, eDP comes back
+without reboot; journal shows display-watch undock `result=ok` when the
+cable leaves. Capture steps in HARDWARE-QUEUE.
+
 ## NEXT
 
 ### 122. A crisper Nomarchy logo in fastfetch