feat(auth): add TOTP two-factor authentication (#495)

[chbndrhnns]

Fixes #495

Summary

Adds TOTP-based two-factor authentication (2FA) for user accounts using Better Auth's twoFactor plugin, including TOTP verification, backup recovery codes, database schema migrations, export/import secret handling, and dashboard account security settings.

Key Changes

• Backend & Auth Configuration (apps/api):

  • Enabled Better Auth twoFactor plugin in apps/api/src/lib/auth.ts.
  • Added secret codec support and registry integration for two_factor.secret and two_factor.backup_codes in system data-transfer.
  • Added tests for 2FA lifecycle and secret encryption/export/import in apps/api/test/lib/two-factor-auth.test.ts and apps/api/src/modules/system/data-transfer/secret-codec.test.ts.

• Database Schema & Migrations (packages/db):

  • Added twoFactorEnabled column to user table and defined twoFactor table in packages/db/src/schema/auth.ts.
  • Added Drizzle migration 0117_mature_wasp.sql and updated snapshot meta and database dump definitions.

• Dashboard UI & Auth Flow (apps/dashboard):

  • Added Account Security section in Settings (/settings) to enable/disable 2FA, display QR code / manual setup key, and generate/view backup codes.
  • Added 2FA challenge page (/two-factor) with support for TOTP code input and backup code fallback.
  • Updated login flow (/login) to route to two-factor challenge when required.
  • Added English locale translations (en/auth.json, en/settings.json) and tests for login redirection, two-factor next routing, and i18n parity.