fix(power): coalesce charge-limit reapply events

USB-C power event bursts could repeatedly restart and SIGTERM the settling oneshot until systemd reached its start limit. Let successful runs return inactive and use coalescing start jobs for immediate and delayed reapplication.

Verified: V0 nix flake check --no-build, module parse, and git diff --check; V2 focused battery-charge-limit KVM test with a 12-event active-run burst. V3 hardware item #101 remains queued.

agent/HARDWARE-QUEUE.md

@@ -11,6 +11,20 @@ the **T14s** (webcam case).
 
 ## Any machine (dev box is fine)
 
+- [ ] **#101 charge-limit service survives USB-C power-event bursts** —
+      after updating/rebuilding to the commit carrying this entry, clear the
+      old failure with `sudo systemctl reset-failed
+      nomarchy-battery-charge-limit.service`. Plug and unplug the powered
+      USB-C dock twice, allowing five seconds after the last transition.
+      **Pass:** `systemctl show nomarchy-battery-charge-limit.service -p
+      ActiveState -p Result` reports `ActiveState=inactive` and
+      `Result=success`; `systemctl is-failed
+      nomarchy-battery-charge-limit.service` is false; BAT0's
+      `charge_control_end_threshold` still matches the configured/live limit;
+      and `journalctl -b -u nomarchy-battery-charge-limit.service` contains
+      no new `SIGTERM`, `start-limit-hit`, or `Failed with result` lines after
+      the rebuild. Capture that journal plus `udevadm monitor
+      --subsystem-match=power_supply` if it fails.
 - [ ] **Docking recovery round 4 (#100, closed-lid BenQ sequence)** — after
       updating to the commit carrying this entry, run `nomarchy-home` and
       relogin. With the lid open, put visible windows on at least workspaces