feat(auth): add lastSeenAt field to user schema and tests

server/apps/api/src/schemas/auth-schema-contract.test.ts

@@ -0,0 +1,13 @@
+import { user } from '@proj-airi/auth-shared'
+import { getTableColumns } from 'drizzle-orm'
+import { describe, expect, it } from 'vitest'
+
+describe('better Auth schema contract', () => {
+  it('keeps the application-owned last_seen_at user column', () => {
+    const columns = getTableColumns(user)
+
+    expect(columns.lastSeenAt).toBeDefined()
+    expect(columns.lastSeenAt.name).toBe('last_seen_at')
+    expect(columns.lastSeenAt.notNull).toBe(false)
+  })
+})