Improvements to persisted state migration (#2098)

* Fix session email/emailConfirmed types, update usage for safer access

* Handle fallback better, better errors

* Better handling, add test

* Add test for default data

* Remove fallback, not needed, update logs

src/state/persisted/__tests__/legacy.test.ts

@@ -0,0 +1,13 @@
+import {expect, test} from '@jest/globals'
+
+import {transform} from '#/state/persisted/legacy'
+import {defaults, schema} from '#/state/persisted/schema'
+
+test('defaults', () => {
+  expect(() => schema.parse(defaults)).not.toThrow()
+})
+
+test('transform', () => {
+  const data = transform({})
+  expect(() => schema.parse(data)).not.toThrow()
+})