launcher: app usage recording moved to ShellState singleton

Commons/ShellState.qml

@@ -90,6 +90,46 @@ Singleton {
     }
   }
 
+  // Launcher app usage tracking (separate file, survives panel destruction)
+  FileView {
+    id: launcherUsageFile
+    path: Settings.cacheDir ? Settings.cacheDir + "launcher_app_usage.json" : ""
+    printErrors: false
+    watchChanges: false
+
+    onLoadFailed: function (error) {
+      if (error.toString().includes("No such file") || error === 2) {
+        writeAdapter();
+      }
+    }
+
+    JsonAdapter {
+      id: launcherUsageAdapter
+      property var counts: ({})
+    }
+  }
+
+  Timer {
+    id: launcherUsageSaveTimer
+    interval: 500
+    onTriggered: launcherUsageFile.writeAdapter()
+  }
+
+  function getLauncherUsageCount(key) {
+    const m = launcherUsageAdapter.counts;
+    if (!m)
+      return 0;
+    const v = m[key];
+    return typeof v === 'number' && isFinite(v) ? v : 0;
+  }
+
+  function recordLauncherUsage(key) {
+    let counts = Object.assign({}, launcherUsageAdapter.counts || {});
+    counts[key] = getLauncherUsageCount(key) + 1;
+    launcherUsageAdapter.counts = counts;
+    launcherUsageSaveTimer.restart();
+  }
+
   // Debounced save timer
   Timer {
     id: saveTimer