feat(db): add Better Auth tables (Session, Account, Verification)

- User extended with emailVerified, name, image (Better Auth fields)
- Session: signed session tokens with expiry, ip and user agent
- Account: credential rows for email+password (provider 'credential') and
  OAuth providers (e.g. Google) — password hash stored on the credential row
- Verification: single-use tokens for email verification, password reset,
  and magic links
- Re-export new types from @ketopath/db

Migration 20260429104721_add_auth_tables run against local Postgres.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/db/src/index.ts

@@ -8,4 +8,4 @@ export {
   Prisma,
   Role,
 } from '@prisma/client';
-export type { Preferences, Profile, User } from '@prisma/client';
+export type { Account, Preferences, Profile, Session, User, Verification } from '@prisma/client';