feat(compass, preferences): implement zoom level persistence COMPASS-9905 (#7363)

* feat: add optional zoom level to InternalUserPreferences

* feat: implement debounced zoom level saving and restoration

* fix: simplify zoom level setting by removing validation checks

* fix: validate zoom level before restoration to ensure it falls within the acceptable range

* fix: remove console log for restoring zoom level

* Update packages/compass/src/app/application.tsx

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix: prevent memory leaks in zoom timeout handling

* imprv: execute zoom process first

* Update packages/compass/src/app/application.tsx

Co-authored-by: Nikola Irinchev <irinchev@me.com>

* fix: clarify comment for zoom level clamping

* Revert "fix: clarify comment for zoom level clamping"

This reverts commit bd6d862.

* fix: clarify comment for zoom level clamping

* fix: simplify zoom level clamping code

* fix: zoomLevel saving process runs in the background

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Nikola Irinchev <irinchev@me.com>

Author: 3 people

packages/compass-preferences-model/src/preferences-schema.tsx

@@ -125,6 +125,7 @@ export type InternalUserPreferences = {
   // TODO: Remove this as part of COMPASS-8970.
   enableConnectInNewWindow: boolean;
   showEndOfLifeConnectionModal: boolean;
+  zoomLevel?: number;
 };
 
 // UserPreferences contains all preferences stored to disk.
@@ -459,6 +460,17 @@ export const storedUserPreferencesProps: Required<{
       ),
     type: 'boolean',
   },
+  /**
+   * Zoom level for restoring browser zoom state.
+   */
+  zoomLevel: {
+    ui: false,
+    cli: false,
+    global: false,
+    description: null,
+    validator: z.number().optional(),
+    type: 'number',
+  },
   /**
    * Enable/disable the AI services. This is currently set
    * in the atlas-service initialization where we make a request to the

packages/compass/src/app/application.tsx

@@ -367,27 +367,66 @@ class Application {
     const ZOOM_INCREMENT = 0.5;
     const ZOOM_MAX = 5;
     const ZOOM_MIN = -3;
+    const SAVE_DEBOUNCE_DELAY = 500; // 500ms delay for save operations
+
+    // Debounced save zoom level to preferences
+    let saveTimeoutId: NodeJS.Timeout | null = null;
+    const debouncedSaveZoomLevel = (zoomLevel: number) => {
+      if (saveTimeoutId) {
+        clearTimeout(saveTimeoutId);
+      }
+
+      saveTimeoutId = setTimeout(() => {
+        void defaultPreferencesInstance.savePreferences({ zoomLevel });
+        saveTimeoutId = null;
+      }, SAVE_DEBOUNCE_DELAY);
+    };
+
+    const restoreZoomLevel = () => {
+      try {
+        const preferences = defaultPreferencesInstance.getPreferences();
+        const savedZoomLevel = preferences.zoomLevel ?? ZOOM_DEFAULT;
+
+        // Clamp zoom level to allowed range
+        const zoomLevel = Math.min(
+          Math.max(savedZoomLevel, ZOOM_MIN),
+          ZOOM_MAX
+        );
+
+        webFrame.setZoomLevel(zoomLevel);
+      } catch {
+        // noop
+      }
+    };
 
     const zoomReset = () => {
-      return webFrame.setZoomLevel(ZOOM_DEFAULT);
+      webFrame.setZoomLevel(ZOOM_DEFAULT);
+      debouncedSaveZoomLevel(ZOOM_DEFAULT);
     };
+
     const zoomIn = () => {
       const currentZoomLevel = webFrame.getZoomLevel();
       const newZoomLevel = Math.min(
         currentZoomLevel + ZOOM_INCREMENT,
         ZOOM_MAX
       );
-      return webFrame.setZoomLevel(newZoomLevel);
+      webFrame.setZoomLevel(newZoomLevel);
+      debouncedSaveZoomLevel(newZoomLevel);
     };
+
     const zoomOut = () => {
       const currentZoomLevel = webFrame.getZoomLevel();
       const newZoomLevel = Math.max(
         currentZoomLevel - ZOOM_INCREMENT,
         ZOOM_MIN
       );
-      return webFrame.setZoomLevel(newZoomLevel);
+      webFrame.setZoomLevel(newZoomLevel);
+      debouncedSaveZoomLevel(newZoomLevel);
     };
 
+    // Restore zoom level on startup
+    restoreZoomLevel();
+
     ipcRenderer?.on('window:zoom-reset', zoomReset);
     ipcRenderer?.on('window:zoom-in', zoomIn);
     ipcRenderer?.on('window:zoom-out', zoomOut);