fix(wallet): keep self-send legs distinct + deterministic tx order

A self-payment surfaces as two transaction records sharing one payment
hash — one outgoing, one incoming. Port the iOS WalletStore.dedupTransactions
hardening so they render correctly:

- Add dedupTransactions(): drop exact (paymentHash, type) repeats the
  backend returns, and sort newest-first with the incoming "received" leg
  above its outgoing "sent" leg on a timestamp tie. Apply on initial load,
  re-enrich, and load-more.
- Key the transaction LazyColumn by "paymentHash|type" so the two legs of a
  self-send keep distinct identities and both render (mirrors iOS
  WalletTransaction.id).

app/src/main/kotlin/com/wisp/app/ui/screen/WalletScreen.kt

@@ -2319,7 +2319,11 @@ private fun TransactionHistoryContent(
             }
             else -> {
                 LazyColumn {
-                    items(transactions) { tx ->
+                    // Key by paymentHash + direction so a self-send's two legs
+                    // (same hash, opposite type) keep distinct identities and
+                    // both render. The list is deduped by (paymentHash, type)
+                    // upstream, so these keys are unique.
+                    items(transactions, key = { "${it.paymentHash}|${it.type}" }) { tx ->
                         TransactionRow(tx, profileLookup, displayMode)
                         HorizontalDivider(
                             modifier = Modifier.padding(horizontal = 16.dp),

app/src/main/kotlin/com/wisp/app/viewmodel/WalletViewModel.kt

@@ -1249,7 +1249,7 @@ class WalletViewModel(
             }
             mapped.fold(
                 onSuccess = { txs ->
-                    _transactions.value = txs
+                    _transactions.value = dedupTransactions(txs)
                     _hasMoreTransactions.value = txs.size >= 50
                     requestMissingProfiles(txs)
                 },
@@ -1266,13 +1266,29 @@ class WalletViewModel(
                     enrichTransactions(current, zapMaps)
                 }
                 if (reEnriched != current) {
-                    _transactions.value = reEnriched
+                    _transactions.value = dedupTransactions(reEnriched)
                     requestMissingProfiles(reEnriched)
                 }
             }
         }
     }
 
+    /**
+     * Collapse exact backend duplicates and order transactions deterministically.
+     *
+     * A self-send surfaces as two records sharing one payment hash — one
+     * outgoing, one incoming. Both legs must survive (we only drop repeats of
+     * the same (paymentHash, type)), and on a timestamp tie the incoming
+     * "received" leg sorts above its outgoing "sent" leg so the conclusion of
+     * the payment reads on top. Mirrors iOS WalletStore.dedupTransactions.
+     */
+    private fun dedupTransactions(txs: List<WalletTransaction>): List<WalletTransaction> =
+        txs.distinctBy { it.paymentHash to it.type }
+            .sortedWith(
+                compareByDescending<WalletTransaction> { it.settledAt ?: it.createdAt }
+                    .thenBy { if (it.type == "incoming") 0 else 1 }
+            )
+
     private fun enrichTransactions(
         txs: List<WalletTransaction>,
         zapMaps: EventRepository.ZapCounterpartyMaps
@@ -1325,7 +1341,7 @@ class WalletViewModel(
             }
             mapped.fold(
                 onSuccess = { txs ->
-                    _transactions.value = _transactions.value + txs
+                    _transactions.value = dedupTransactions(_transactions.value + txs)
                     _hasMoreTransactions.value = txs.size >= 50
                     val missing = txs.mapNotNull { it.counterpartyPubkey }
                         .distinct()