* fix(arch-updater): tighten package list spacing and icon size
* fix(arch-updater): make Dismiss actually clear the pending list
* fix(arch-updater): make hitting update close the panel
* feat(arch-updater): add per-source icons to the package list header
* feat(arch-updater): add an activity graph to the panel
Tracks the pending-update count across recent checks and when the last
update ran, persisted to disk so it survives restarts. Off also stops
recording history, not just hiding it.
* feat(arch-updater): show per-point detail on activity graph hover
ui.graph has no pointer props of its own, so a row of ghost buttons
sits under the line as per-point hit targets, each with a native
tooltip. History entries now carry a timestamp and whether the check
followed an update run, so hovering a point says when it happened and
either its pending count or "Updated".
* fix(arch-updater): load activity history at startup, not on first check
loadHistoryState() only ran lazily inside recordCheck/recordUpdateRun,
so a freshly started service published an empty history until a check
completed, hiding the graph even when prior sessions had data on disk.
* fix(arch-updater): render activity graph with sharp points, not curves
