feat(wallet): token send support with asset picker

- Add UtxoAsset model for native assets in UTXOs
- Update KoiosCardanoClient.getUtxos() to parse asset_list
- Add asset fields to PaymentRequest (policyId, name, quantity)
- DefaultTransactionBuilder: multi-asset tx with Amount.asset()
- Min UTXO: always include 1.5 ADA with token sends (protocol req)
- PaymentEntryPresenter: load available assets, handle selection
- PaymentEntryView: asset picker dropdown when tokens available
- PaymentConfirmation: show token name/quantity instead of ADA
- PaymentProgress: displayAmount field for token sends
- Wire asset data through entire nav flow (FlowNode/Nodes)
- Updated NativeAsset with metadata fields for NFT prep

features/wallet/api/src/main/kotlin/io/element/android/features/wallet/api/NativeAsset.kt

@@ -14,6 +14,11 @@ package io.element.android.features.wallet.api
  * @property quantity The amount of this asset
  * @property displayName Human-readable name if available
  * @property fingerprint The asset fingerprint (CIP-14)
+ * @property imageUrl Resolved image URL (IPFS gateway or HTTPS) for NFTs
+ * @property decimals Decimal places for fungible tokens (null for NFTs)
+ * @property ticker Token ticker symbol (e.g., "HOSKY")
+ * @property description Token/NFT description
+ * @property isNft True if this is likely an NFT (quantity == 1 with image metadata)
  */
 data class NativeAsset(
     val policyId: String,
@@ -21,6 +26,11 @@ data class NativeAsset(
     val quantity: Long,
     val displayName: String?,
     val fingerprint: String?,
+    val imageUrl: String? = null,
+    val decimals: Int? = null,
+    val ticker: String? = null,
+    val description: String? = null,
+    val isNft: Boolean = false,
 ) {
     /**
      * Truncated policy ID for display.
@@ -36,7 +46,7 @@ data class NativeAsset(
      * Display name, falling back to truncated asset name.
      */
     val name: String
-        get() = displayName ?: assetName.takeIf { it.isNotEmpty() }?.let {
+        get() = displayName ?: ticker ?: assetName.takeIf { it.isNotEmpty() }?.let {
             // Try to decode hex to ASCII if it looks printable
             try {
                 val decoded = it.chunked(2).map { hex -> hex.toInt(16).toChar() }.joinToString("")
@@ -45,4 +55,22 @@ data class NativeAsset(
                 it
             }
         } ?: "Unknown"
+
+    /**
+     * Unit string for this asset (concatenated policyId + assetName).
+     */
+    val unit: String
+        get() = "$policyId$assetName"
+
+    /**
+     * Format quantity with decimals for display.
+     */
+    fun formatQuantity(): String {
+        return if (decimals != null && decimals > 0) {
+            val divisor = Math.pow(10.0, decimals.toDouble())
+            String.format("%.${decimals}f", quantity / divisor).trimEnd('0').trimEnd('.')
+        } else {
+            quantity.toString()
+        }
+    }
 }

features/wallet/api/src/main/kotlin/io/element/android/features/wallet/api/PaymentRequest.kt

@@ -13,12 +13,25 @@ import io.element.android.libraries.matrix.api.core.SessionId
  *
  * @property fromAddress The sender's Cardano address (Bech32)
  * @property toAddress The recipient's Cardano address (Bech32)
- * @property amountLovelace The amount to send in lovelace (1 ADA = 1,000,000 lovelace)
+ * @property amountLovelace The amount of ADA to send in lovelace (1 ADA = 1,000,000 lovelace).
+ *                          For token-only sends, this should be the minimum UTXO (~1.5 ADA).
  * @property sessionId The Matrix session ID for key retrieval
+ * @property assetPolicyId Policy ID of the native asset to send (null for ADA-only)
+ * @property assetName Asset name in hex (null for ADA-only)
+ * @property assetQuantity Quantity of the native asset to send (null for ADA-only)
  */
 data class PaymentRequest(
     val fromAddress: String,
     val toAddress: String,
     val amountLovelace: Long,
     val sessionId: SessionId,
-)
+    val assetPolicyId: String? = null,
+    val assetName: String? = null,
+    val assetQuantity: Long? = null,
+) {
+    /**
+     * True if this request includes a native asset (token) send.
+     */
+    val hasAsset: Boolean
+        get() = assetPolicyId != null && assetName != null && assetQuantity != null && assetQuantity > 0
+}

features/wallet/api/src/main/kotlin/io/element/android/features/wallet/api/Utxo.kt

@@ -13,10 +13,25 @@ package io.element.android.features.wallet.api
  * @property outputIndex The index of this output within the transaction.
  * @property amount The amount in lovelace (1 ADA = 1,000,000 lovelace).
  * @property address The address holding this UTxO.
+ * @property assets Native assets (tokens) contained in this UTxO.
  */
 data class Utxo(
     val txHash: String,
     val outputIndex: Int,
     val amount: Long,
     val address: String,
+    val assets: List<UtxoAsset> = emptyList(),
+)
+
+/**
+ * Represents a native asset within a UTxO.
+ *
+ * @property policyId The minting policy ID (56 hex chars).
+ * @property assetName The asset name (hex-encoded).
+ * @property quantity The amount of this asset in the UTxO.
+ */
+data class UtxoAsset(
+    val policyId: String,
+    val assetName: String,
+    val quantity: Long,
 )