fix(arch-updater): tighten package list UI and fix Dismiss/Update panel behavior (#289)

* 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

arch-updater/README.md

@@ -47,8 +47,8 @@ The panel groups pending packages by source (Pacman, AUR, Flatpak). Click a
 source row to expand it into its packages. Each package row has a copy
 button (name and versions) and an open button (its page on archlinux.org,
 the AUR, or Flathub). **Check Updates** queries all sources, **Update** opens
-a terminal running the upgrade, **Dismiss** keeps the numbers but returns the
-bar glyph to its resting colour.
+a terminal running the upgrade, **Dismiss** clears the pending list and
+closes the panel, returning the bar glyph to its resting colour.
 
 Type `/arch` in the launcher for quick actions (check, update, open news), or
 `/arch <text>` to fuzzy-search the packages from the last check. Activating a
@@ -78,6 +78,10 @@ Not in the v4 plugin:
 - **A generic package-page link** (`archlinux.org/packages`,
   `aur.archlinux.org`, `flathub.org`) instead of hardcoded per-repo mirror
   URLs, so it stays correct across Arch-based distros.
+- **An activity graph.** A small trend line of the pending-update count
+  across the most recent checks, plus when you last ran an update. Persisted
+  to disk so it survives restarts. On by default, and turning it off also
+  stops recording the history, not just hiding it.
 
 ## Settings
 
@@ -92,6 +96,8 @@ Not in the v4 plugin:
 | `show_download_size` | `bool` | `true` | Show the estimated pacman download size (`pacman -Si`) in the panel. |
 | `check_arch_news` | `bool` | `true` | Check the Arch Linux news feed and flag unread posts. |
 | `check_reboot_needed` | `bool` | `true` | Flag when the running kernel is no longer installed on disk. |
+| `show_activity_graph` | `bool` | `true` | Track and show the pending-update trend and last-update time in the panel. Off also stops recording history. |
+| `activity_history_length` | `int` | `10` | How many of the most recent checks to keep for the activity graph. |
 | `terminal` | `string` | *(empty)* | Terminal command for the update run, e.g. `kitty`. Empty uses Noctalia's detection. |
 | `assume_yes` | `bool` | `false` | Pass `--noconfirm` / `-y` so package managers do not ask for confirmation. |
 | `update_cmd` | `string` | *(empty)* | Full override for the update command. Empty builds it from the settings above. |