feat: expose the Rust identity key layout to FFI, Swift and Kotlin hosts

packages/kotlin-sdk/KotlinExampleApp/app/src/main/java/org/dashfoundation/example/services/DashpayKeyProvisioning.kt

@@ -2,13 +2,14 @@ package org.dashfoundation.example.services
 
 import org.dashfoundation.dashsdk.identity.IdentityKeyPreview
 import org.dashfoundation.dashsdk.identity.RegistrationKeySet
+import org.dashfoundation.dashsdk.identity.RegistrationKeySlot
 import org.dashfoundation.dashsdk.identity.RegistrationKeys
 
 /**
  * Registration key provisioning — the derive-set → persist → zero →
  * build-rich-rows sequence the create-identity flow runs before it broadcasts.
  * App-level analog of Swift's `CreateIdentityView` submit path
- * (`prePersistIdentityKeysForRegistration` + `makeDashpayKeyPair`).
+ * (`prePersistIdentityKeysForRegistration`).
  *
  * ## Why a dedicated helper rather than reusing `IdentityKeyAdditionFlow`
  *
@@ -22,11 +23,11 @@ import org.dashfoundation.dashsdk.identity.RegistrationKeys
  *   `previewRegistrationKeySet` pass — the secret-lifecycle mandate is one
  *   derivation, not N overlapping ones;
  * - its policy depends on the existing identity's current key IDs and builds
- *   an update batch, while registration needs a fixed 0..N role table before
- *   the identity exists.
+ *   an update batch, while registration needs the Rust-owned creation layout
+ *   before the identity exists.
  *
  * Forcing registration through it would fork its semantics; this helper reuses
- * the shared pieces instead — the SDK's [RegistrationKeys] role table for the
+ * the shared pieces instead — the Rust layout via [RegistrationKeys] for the
  * on-chain rows and [IdentityKeyPersistence] for the store-then-zero secret
  * discipline (shared with [IdentityKeyAdditionFlow]).
  */
@@ -37,8 +38,8 @@ object DashpayKeyProvisioning {
      * rich rows the registration wire format carries, tied to the identity HD
      * slot that produced them.
      *
-     * [previews] must be exactly `RegistrationKeys.keyCount(includeDashPayKeys)`
-     * rows in key-ID order — the single [IdentityKeyPreview] derivation pass
+     * [previews] must be exactly one row per [slots] entry, in key-ID order
+     * ([slots] is `RegistrationKeys.layout(...)` for the flow's layout) — the single [IdentityKeyPreview] derivation pass
      * (`previewRegistrationKeySet`). Every preview's private array is zeroed on
      * both the success and every failure path (including the count-mismatch
      * rejection); a partial persist failure never leaves a plaintext scalar
@@ -53,11 +54,11 @@ object DashpayKeyProvisioning {
      */
     suspend fun provision(
         previews: List<IdentityKeyPreview>,
-        includeDashPayKeys: Boolean,
+        slots: List<RegistrationKeySlot>,
         walletId: ByteArray,
         persister: IdentityKeyPersistence.PrivateKeyPersister,
     ): RegistrationKeySet {
-        val expected = RegistrationKeys.keyCount(includeDashPayKeys)
+        val expected = slots.size
         try {
             // Inside the try so the catch below scrubs the derived scalars even
             // on a count-mismatch rejection (a wire-skew symptom) — no plaintext
@@ -89,7 +90,7 @@ object DashpayKeyProvisioning {
             identityIndex = previews.first().identityIndex,
             rows = RegistrationKeys.buildRegistrationRows(
                 previews.map { it.publicKey },
-                includeDashPayKeys,
+                slots,
             ),
         )
     }

packages/kotlin-sdk/KotlinExampleApp/app/src/main/java/org/dashfoundation/example/ui/dashpay/ClaimInvitationSheet.kt

@@ -25,6 +25,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import kotlinx.coroutines.NonCancellable
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import org.dashfoundation.dashsdk.identity.IdentityCreationKeyLayout
 import org.dashfoundation.dashsdk.identity.RegistrationKeys
 import org.dashfoundation.dashsdk.tokens.InvitationPreview
 import org.dashfoundation.example.di.LocalAppContainer
@@ -144,17 +145,18 @@ fun ClaimInvitationSheet(
                             .filter { it.walletId?.contentEquals(wallet.walletId) == true }
                             .map { it.identityIndex } + heldByCoordinator,
                     )
-                    // Full fresh-registration set: base four + the DashPay
-                    // enc/dec pair, pre-persisted before the broadcast.
+                    // Full fresh-registration set (Rust layout, DashPay
+                    // enc/dec pair included), pre-persisted before the broadcast.
+                    val layout = IdentityCreationKeyLayout.NEW_IDENTITY_WITH_DASHPAY_KEYS
                     val previews = mgr.identityRegistration.previewRegistrationKeySet(
                         walletHandle = wallet.handle,
                         mnemonicResolverHandle = mgr.mnemonicResolverHandle,
                         identityIndex = identityIndex,
-                        count = RegistrationKeys.keyCount(includeDashPayKeys = true),
+                        layout = layout,
                     )
                     val keySet = DashpayKeyProvisioning.provision(
                         previews = previews,
-                        includeDashPayKeys = true,
+                        slots = RegistrationKeys.layout(layout),
                         walletId = wallet.walletId,
                         persister = { keyHex, priv, owner ->
                             container.walletStorage.storePrivateKey(

packages/kotlin-sdk/KotlinExampleApp/app/src/main/java/org/dashfoundation/example/ui/dashpay/ReclaimInvitationSheet.kt

@@ -24,6 +24,8 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import kotlinx.coroutines.NonCancellable
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import org.dashfoundation.dashsdk.identity.IdentityCreationKeyLayout
+import org.dashfoundation.dashsdk.identity.RegistrationKeys
 import org.dashfoundation.dashsdk.persistence.entities.InvitationEntity
 import org.dashfoundation.dashsdk.wallet.ManagedPlatformWallet
 import org.dashfoundation.example.di.LocalAppContainer
@@ -151,19 +153,19 @@ fun ReclaimInvitationSheet(
                             walletIdentities.map { it.identityIndex } + heldByCoordinator,
                         )
                         // Pre-broadcast local work — BEFORE the marker, so a
-                        // failure here leaves no in-flight marker. Base 4-key
-                        // set: a reclaim sends no contact request (iOS
-                        // authKeyCount = 4).
+                        // failure here leaves no in-flight marker. New-identity
+                        // set without DashPay keys: a reclaim sends no contact
+                        // request.
+                        val layout = IdentityCreationKeyLayout.NEW_IDENTITY
                         val previews = mgr.identityRegistration.previewRegistrationKeySet(
                             walletHandle = wallet.handle,
                             mnemonicResolverHandle = mgr.mnemonicResolverHandle,
                             identityIndex = identityIndex,
-                            count = org.dashfoundation.dashsdk.identity.RegistrationKeys
-                                .keyCount(includeDashPayKeys = false),
+                            layout = layout,
                         )
                         val keySet = DashpayKeyProvisioning.provision(
                             previews = previews,
-                            includeDashPayKeys = false,
+                            slots = RegistrationKeys.layout(layout),
                             walletId = wallet.walletId,
                             persister = { keyHex, priv, owner ->
                                 container.walletStorage.storePrivateKey(