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.

client/package.json

@@ -26,6 +26,7 @@
     "@fontsource/geist-sans": "^5.2.5",
     "@fontsource/poppins": "^5.2.7",
     "@react-pdf/renderer": "^4.5.1",
+    "@simplewebauthn/browser": "^13.1.2",
     "@trek/shared": "*",
     "axios": "^1.6.7",
     "dexie": "^4.4.2",