appProcess.registerOnStateChange

import { appProcess } from '@canva/platform';

const stateDisposer = appProcess.registerOnStateChange(
  processId,
  ({ state }) => {
    switch (state) {
      case 'opening':
        // Process is starting up
        break;
      case 'open':
        // Process is active and visible
        break;
      case 'closing':
        // Process is about to close
        // Save state, cleanup resources
        break;
      case 'closed':
        // Process has been terminated
        // Final cleanup if needed
        break;
    }
  }
);

// Later: cleanup the listener
await stateDisposer();