fix(files): address autosave migration and review regressions

Seed omitted autoSaveEnabled from the hydrated client preference (including
legacy localStorage) instead of resetting everyone to enabled. Restore SVG
non-editable flags, treat clean draft saves as success, and throw again from
disposed content-cache owners while keeping runtime-switch cache invalidation.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/lib/persistence.test.ts

@@ -528,16 +528,43 @@ describe('updateDesktopSettings', () => {
     expect(saveCalls.some((changes) => changes.autoSaveEnabled === false)).toBe(true);
   });
 
-  test('resets omitted autoSaveEnabled to the default enabled state', async () => {
+  test('seeds omitted autoSaveEnabled from the hydrated client preference', async () => {
     getWindow();
+    invalidateSettingsCache();
     useUIStore.getState().setAutoSaveEnabled(false);
-    registerSettingsApi(async () => ({}), async () => ({
+    const saveCalls: Array<Partial<SettingsPayload>> = [];
+    registerSettingsApi(async (changes) => {
+      saveCalls.push(changes);
+      return { ...changes } as SettingsPayload;
+    }, async () => ({
       settings: { draftStartersCraftGoalAdded: true, draftStartersScheduleTaskAdded: true },
       source: 'web',
     }));
 
     await syncDesktopSettings();
+    await delay(500);
+
+    expect(useUIStore.getState().autoSaveEnabled).toBe(false);
+    expect(saveCalls.some((changes) => changes.autoSaveEnabled === false)).toBe(true);
+  });
+
+  test('seeds default autoSaveEnabled when omitted and client still has the default', async () => {
+    getWindow();
+    invalidateSettingsCache();
+    useUIStore.getState().setAutoSaveEnabled(true);
+    const saveCalls: Array<Partial<SettingsPayload>> = [];
+    registerSettingsApi(async (changes) => {
+      saveCalls.push(changes);
+      return { ...changes } as SettingsPayload;
+    }, async () => ({
+      settings: { draftStartersCraftGoalAdded: true, draftStartersScheduleTaskAdded: true },
+      source: 'web',
+    }));
+
+    await syncDesktopSettings();
+    await delay(500);
 
     expect(useUIStore.getState().autoSaveEnabled).toBe(true);
+    expect(saveCalls.some((changes) => changes.autoSaveEnabled === true)).toBe(true);
   });
 });