Integrate Android biometrics with the shared Rust lease (#98)

android/README.md

@@ -1,12 +1,13 @@
 # Native Android build
 
 Architecture and issue ownership: [ADR](../docs/android/architecture.md) and
-[parity matrix](../docs/android/parity.md). The native foundation, onboarding, navigation and Home implement #89–#97, including private storage, Keystore
+[parity matrix](../docs/android/parity.md). The native foundation, onboarding, navigation, Home and authentication implement #89–#98, including private storage, Keystore
 callbacks and build gates. Both variants invoke Rust through the generated
 UniFFI API. Local-first and HTTPS onboarding is described in
 [onboarding](../docs/android/onboarding.md). The Passwords tab uses Rust-owned,
 revision-checked [adaptive navigation](../docs/android/password-navigation.md);
 Home renders Rust-owned [Git activity and HTTPS synchronization](../docs/android/home-sync.md).
+Passwords and Preferences share [Rust-owned biometric authentication](../docs/android/authentication.md).
 Remaining feature screens retain their milestone issues. The full [CI and emulator workflow](../docs/android/ci.md) documents the
 ARM-only runner/toolchain policy and artifact audits.