feat(decky): visible branded Steam shortcut, one-tap client updates, fullscreen-page polish

- The "Punktfunk" shortcut is no longer hidden: it now ships committed
  artwork (grid/wide/hero/logo/icon, generated by scripts/gen-steam-art.py
  — a pure-stdlib SDF renderer drawing the lens mark + a monoline
  "punktfunk" wordmark) applied via SetCustomArtworkForApp /
  SetShortcutIcon. Existing installs are unhidden and re-arted once per
  ART_VERSION; relaunching the library entry streams to the last host.
- Updates cover the flatpak CLIENT too: check_update compares the
  user-scope installed commit against its remote, applyUpdate runs
  `flatpak update --user` first (awaited) and the plugin reinstall —
  which reloads the panel — last; docs spell out the sudo-less --user
  update ("sudo flatpak update" silently skips per-user installs).
- Fullscreen page: DialogButton stretches to 100% width in the gamepad
  UI, so the Stream/Pair/Refresh/… actions filled whole rows — sized to
  content + right-aligned now; the header drops its Update button (About
  tab + QAM banner keep the flow) and the back button gets a real 40px
  hit target.
- Settings: the disable-Steam-Input note also shows for Automatic — on a
  Deck that now forwards the built-in controller as a Steam Deck pad
  (paddles/trackpads/gyro), which needs Steam Input off for the shortcut.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

clients/decky/src/index.tsx

@@ -14,7 +14,7 @@ import { definePlugin, routerHook } from "@decky/api";
 import { FC } from "react";
 import { FaDownload, FaLock, FaLockOpen, FaSyncAlt, FaTv } from "react-icons/fa";
 import { PluginErrorBoundary } from "./boundary";
-import { applyUpdate, checkForUpdatesNow, startStream, useHosts, useUpdate } from "./hooks";
+import { applyUpdate, checkForUpdatesNow, hasUpdate, startStream, useHosts, useUpdate } from "./hooks";
 import { PunktfunkRoute, ROUTE } from "./page";
 import { PairModal } from "./pair";
 
@@ -27,13 +27,19 @@ const QamPanel: FC = () => {
 
   return (
     <>
-      {update?.update_available && (
+      {hasUpdate(update) && (
         <PanelSection title="Update available">
           <PanelSectionRow>
             <ButtonItem
               layout="below"
-              onClick={() => applyUpdate(update)}
-              label={`v${update.current} → v${update.latest}`}
+              onClick={() => applyUpdate(update!, check)}
+              label={
+                update!.update_available
+                  ? `Plugin v${update!.current} → v${update!.latest}${
+                      update!.client_update_available ? " + client" : ""
+                    }`
+                  : "New client version"
+              }
               description="Installing can take a couple of minutes"
             >
               <FaDownload style={{ marginRight: "0.5em" }} />