fix: audit remediation — security, quality and performance fixes

- CI Dockerfile: verify act_runner SHA256, restrict sudoers to safe
  pacman arguments (S-C1, S-C2)
- cliphist: split into cliphist-text + cliphist-image services with
  Type=simple for proper PID tracking and restart (Q-C3)
- batsaver-toggle: validate sysfs input as numeric, check state file
  write (Q-C2, S-W2)
- udev battery rule: add ACTION=="add" filter to avoid firing on
  every battery event (Q-W3)
- cpugov: replace eval with direct expansion, switch waybar module
  to signal-based updates, send SIGRTMIN+10 after toggle (Q-W1,
  S-W1, P-W4)
- Remove docker group auto-assignment from install scripts (S-I1)

defaults/xdg/waybar/config

@@ -296,7 +296,8 @@
     "custom/cpugov": {
         "exec": "moonarch-waybar-cpugov",
         "return-type": "json",
-        "interval": 5,
+        "interval": 60,
+        "signal": 10,
         "on-click": "moonarch-cpugov"
     },
     "custom/gpu-usage": {