feat: Passkey (WebAuthn) login (#1111)

* feat(auth): passkey (WebAuthn) login — server endpoints, schema + admin toggle

Add @simplewebauthn/server registration and primary (discoverable) login ceremonies under /api/auth/passkey, a webauthn_credentials + single-use webauthn_challenges schema (migration), the instance-wide passkey_login toggle (default off) enforced before auth by a guard, and require_mfa satisfaction via a verified passkey. RP ID/origin come only from server config (webauthn_rp_id/origins -> APP_URL), never request headers.

* feat(auth): passkey enrolment, login button + admin settings UI

PasskeysSection in account settings (add/rename/remove with a current-password step-up), a 'Sign in with a passkey' button on the login page, the admin enable + RP-ID/origins controls, and a per-user admin reset action.

* i18n(auth): passkey strings across all locales

Add login/settings/admin passkey keys to en and all 19 translated locales.

server/package.json

@@ -27,6 +27,7 @@
     "@nestjs/common": "^11.1.24",
     "@nestjs/core": "^11.1.24",
     "@nestjs/platform-express": "^11.1.24",
+    "@simplewebauthn/server": "^13.1.2",
     "archiver": "^6.0.1",
     "bcryptjs": "^2.4.3",
     "better-sqlite3": "^12.8.0",