android: V4.9 + V4.10 Kotlin ports + KeystoreStorage adapter

Pure-JVM additions to shade-android (no Android SDK needed):
- V4.9 blob primitives: BlobKdf (HKDF deriveBlobSlotId/Key/SigningSeed),
  BlobAead (nonce||ct||tag with shade-profile-aad-v1:<slot> AAD),
  BlobClient (java.net.http with hand-written canonical JSON signing
  matching TS signPayload output), Profile high-level namespace.
- V4.10 approval helpers: CanonicalProfileBlob schema with denormalized
  trustedApproverFingerprints, build/sign/verify proxy approvals via
  length-prefixed u16 BE UTF-8 canonical signing payload.
- Password KDFs: scrypt + argon2id via Bouncy Castle, NFKC-normalized.
- SessionStateJson at-rest serializer for persistence layer.

Cross-platform vectors (test-vectors/blob.json, approval.json) gate
byte-identical output between TS and Kotlin, including a TS-signed
Ed25519 signature the Kotlin port verifies and reproduces (Ed25519 is
deterministic).

New shade-android-keystore sibling Gradle module (Android-specific):
- KeystoreMasterKey: hardware-backed AES-256-GCM with BIOMETRIC_STRONG
  gating, StrongBox-backed when available, invalidated on enrollment.
- BiometricUnlock: coroutine wrapper around BiometricPrompt with
  tagged cancellation/failure exceptions.
- KeystoreStorage: StorageProvider over biometric-gated AES-encrypted
  SharedPreferences with AAD-bound row keys.

All 25 SDK packages typecheck clean; 104 SDK tests + 24 new Kotlin
tests + 11 cross-platform vector tests all green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/settings.gradle.kts

@@ -4,6 +4,7 @@ pluginManagement {
     repositories {
         gradlePluginPortal()
         mavenCentral()
+        google()
     }
 }
 
@@ -17,3 +18,6 @@ dependencyResolutionManagement {
 
 include(":shade-android")
 project(":shade-android").projectDir = file("shade-android")
+
+include(":shade-android-keystore")
+project(":shade-android-keystore").projectDir = file("shade-android-keystore")