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/HARDWARE-QUEUE.md

@@ -11,6 +11,33 @@ the **T14s** (webcam case).
 
 ## Any machine (dev box is fine)
 
+- [ ] **#127 docked idle blackout (AMD dev box, 2026-07-15)** —
+      **Incident (FAILED, unsolicited):** laptop docked, idle a few minutes,
+      screens went black ("sleep"). External keyboard/mouse did not restore
+      any display; unplugging the external did not re-enable the laptop
+      panel; Caps Lock LED still toggled (machine alive). Forced recovery
+      was needed; a long Grok session died with the brick.
+      **Important distinction:** on AC, hypridle is *not* supposed to
+      suspend — only lock (5m) + `dpms off` (10m). Confirm next time with
+      `journalctl -b | rg -i 'Suspending|PM: suspend'` vs hypridle/hyprlock
+      lines so we know DPMS-stuck vs real S3.
+      **Repro / capture (next time, before reboot if possible — SSH/TTY):**
+      1. Dock, confirm dock mode (eDP disabled in `hyprctl monitors all -j`).
+      2. Leave idle past 10 minutes (or force: `loginctl lock-session` then
+         `hyprctl dispatch dpms off`).
+      3. Try external KB key / mouse move — does external wake?
+      4. Unplug external — does eDP return within a few seconds?
+      5. Capture (SSH from another machine if the seat is blind):
+         ```
+         journalctl --user -t nomarchy-display-watch -t nomarchy-display-transition \
+           -t hypridle --since '-30 min'
+         journalctl -b --since '-30 min' | rg -i 'suspend|sleep|dpms|lid|hyprlock'
+         hyprctl monitors all -j; hyprctl keyword monitor 2>&1 | head
+         systemd-inhibit --list
+         ```
+      **Pass:** input wakes the external while docked; undock while black
+      restores eDP without power cycle. Related: docking recovery round 8
+      (awake undock) and BACKLOG #127.
 - [ ] **#96 battery-limit row on threshold-less firmware (Acer M5-481T)** —
       on the Acer (live or installed session with the commit carrying this
       entry): open System (`SUPER+CTRL+I`). **Pass:** a "Battery limit" row