feat(expo): move biometric credentials to @clerk/expo-biometrics

[mikepitre]

Description

useBiometricCredentials() (and the deprecated useTrustedDevices() wrapper) now run enrollment, listing, revocation and sign-in in JS. clerk-js talks to FAPI through the experimental trusted device resources from #9953, and @clerk/expo-biometrics (#9959) handles only keys, signing and on-device records. Before this change, these calls went through the ClerkExpo native module in @clerk/expo-native-components.

• @clerk/expo-biometrics is an optional peer dependency. It is loaded with a guarded require. When it is missing, or the development build doesn't include its native module, the hook's methods throw an error that explains how to install it and rebuild. Web keeps the existing unsupported stub.
• The orchestration follows clerk-ios BiometricCredentials.swift:
  • Environment gating uses nativeSettings.
  • Local candidates are filtered by app identifier, then id, then identifier hint, newest first.
  • Records whose key is missing are pruned, and records are filtered by which policies the device can evaluate.
  • When a session is active, records are reconciled with the server list.
  • Enrollment runs createKey → prepare → sign → attempt → saveRecord({ removeOtherRecordsForApp: true }). If prepare, sign or attempt fails, the key is deleted. If saving the record fails, the server credential is revoked and the key is deleted.
  • Sign-in runs signIn.create → sign trustedDeviceChallenge.clientData → attemptFirstFactor. The local record is forgotten on form_resource_not_found / trusted_device_not_registered for trusted_device_id, and on key_invalidated / key_not_found.
• Identifier hints are matched on identifierHintSha256 with hashIdentifierHint(). A small compatibility shim falls back to the normalized raw identifierHint until the Android PR adds those members.
• The error contract is unchanged. FAPI errors, including reverification-required errors from prepare/revoke, are thrown as biometric credential errors whose code is the API error code, as the native bridge did, with the original ClerkAPIResponseError as cause. Device errors are mapped to the existing BiometricCredentialErrorCode values.
• reverify() stays on the @clerk/expo-native-components path unchanged. FAPI only lists trusted_device reverification factors from API version 2026-08-20. Its error now names @clerk/expo-native-components when that package is missing.
• The now-unused enroll/list/revoke/sign-in/availability entries are removed from the ClerkExpo module spec types. The Swift/Kotlin implementations will be removed in a follow-up.

Stack: #9955 ← #9957 ← #9954 ← #9956 ← #9958 ← #9953 ← #9959 ← this PR. This PR will be rebased onto the @clerk/expo-biometrics Android PR once it's open.

Checklist

• pnpm test runs as expected.
• pnpm build runs as expected.
• (If applicable) JSDoc comments have been added or updated for any package exports
• (If applicable) Documentation has been updated

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

🤖 Generated with Claude Code

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🦋 Changeset detected

Latest commit: 997b6d9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@clerk/expo	Minor

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Project	Deployment	Actions	Updated
clerk-js-sandbox	Ready	Preview	Sep 28, 2026 8:26pm UTC
swingset	Ready	Preview	Sep 28, 2026 8:26pm UTC

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[mikepitre]

Recorded on a physical iPhone Air (iOS 27) with the full stack (#9955 → #9962) in an Expo SDK 57 app: useBiometricCredentials running on clerk-js plus @clerk/expo-biometrics (Secure Enclave key, Face ID). The simulator can't run this flow because it has no Secure Enclave.

1. Email-code sign-in → getAvailability() reports no_local_credential
2. enroll() → Face ID → credential active on the server
3. Sign out → getAvailability() reports available
4. signIn() → Face ID → JS signed in, and the native UserButton picks up the session

A system notification near the top of the screen is blurred between about 0:04 and 0:26.

biometrics-device-redacted.mp4