feat(migration): complete Step 1 of ActiveDid migration - update () to use new API

- Update () to call () with fallback to settings
- Maintain backward compatibility while using new active_identity table
- Update migration plan documentation to reflect completed Step 1
- Restore Playwright workers to 4 (was accidentally set to 1)

Tests: 39/40 passing (1 unrelated UI failure)
Migration progress: Step 1 complete, ready for Step 2 dual-write implementation

playwright.config-local.ts

@@ -21,7 +21,7 @@ export default defineConfig({
   /* Retry on CI only */
   retries: process.env.CI ? 2 : 0,
   /* Opt out of parallel tests on CI. */
-  workers: 1,
+  workers: 4,
   /* Reporter to use. See https://playwright.dev/docs/test-reporters */
   reporter: [
     ['list'],