feat: enhance global settings update with data loss prevention

- Added safeguards to prevent overwriting non-empty arrays with empty arrays during global settings updates, specifically for the 'projects' field.
- Implemented logging for updates to assist in diagnosing accidental wipes of critical settings.
- Updated tests to verify that projects are preserved during logout transitions and that theme changes are ignored if a project wipe is attempted.
- Enhanced the settings synchronization logic to ensure safe handling during authentication state changes.

apps/ui/src/hooks/use-settings-migration.ts

@@ -94,6 +94,17 @@ export function waitForMigrationComplete(): Promise<void> {
   return migrationCompletePromise;
 }
 
+/**
+ * Reset migration state when auth is lost (logout/session expired).
+ * This ensures that on re-login, the sync hook properly waits for
+ * fresh settings hydration before starting to sync.
+ */
+export function resetMigrationState(): void {
+  migrationCompleted = false;
+  migrationCompletePromise = null;
+  migrationCompleteResolve = null;
+}
+
 /**
  * Parse localStorage data into settings object
  */