fix(desktop): hardware findings — charge limit, polkit ws, bar deps

Latitude 5310 QA:
- Clock tooltip: drop empty {calendar} popup; plain date+zone
- Charge limit: restart oneshot via polkit + dual write/delay for
  Dell unplug race; toast verifies sysfs; looser menu match
- pwvucontrol ships with waybar (right-click volume)
- Print/region→clipboard toasts success
- Polkit (and pinentry) open on current workspace + stayfocused

V0: flake check --no-build green. V3: retest A3/A4/B1/tooltip/polkit.

templates/downstream/home.nix

@@ -85,8 +85,7 @@
     inkscape            # vector graphics
     mpv                 # media player
     amberol             # music player (local library; streaming → spotify below)
-    pwvucontrol         # PipeWire volume mixer (right-click the Waybar volume)
-    # calcurse ships with the Waybar clock (modules/home/waybar.nix)
+    # pwvucontrol + calcurse ship with the Waybar module (volume right-click / clock)
 
     # ── More apps — uncomment to add ─────────────────────────────────
     # Web browsers