fix: harden Paykit request handling

Bitkit/Services/PrivatePaykitService+Contacts.swift

@@ -352,7 +352,6 @@ extension PrivatePaykitService {
             let linkableReceiverPaths = receiverPathSelection.linkableReceiverPaths
             let publicationReceiverPaths = receiverPathSelection.publishableReceiverPaths
             if let error = receiverPathSelection.error {
-                firstError = firstError ?? error
                 Logger.warn(
                     "Failed to inspect private Paykit receiver markers for \(PubkyPublicKeyFormat.redacted(publicKey)) during \(reason): \(error)",
                     context: "PrivatePaykit"

Bitkit/ViewModels/AppViewModel.swift

@@ -468,6 +468,7 @@ extension AppViewModel {
             data = try await decode(invoice: uri)
             try ensureScannedDataHandlingOwnership(handlingId, claimedContactPaymentContext: claimedContactPaymentContext)
         }
+        let requestedAmount = contactPaymentContext?.incomingPaymentRequest?.amountSats
 
         switch data {
         // BIP21 (Unified) invoice handling
@@ -500,7 +501,7 @@ extension AppViewModel {
                         if nodeIsRunning {
                             // Node is running → we have fresh balances; validate immediately.
                             // Prefer lightning; if insufficient or no channels/capacity, fall back to onchain.
-                            let canSendLightning = lightningService.canSend(amountSats: lightningInvoice.amountSatoshis)
+                            let canSendLightning = lightningService.canSend(amountSats: requestedAmount ?? lightningInvoice.amountSatoshis)
 
                             if canSendLightning {
                                 handleScannedLightningInvoice(lightningInvoice, bolt11: lnInvoice, onchainInvoice: invoice)
@@ -520,7 +521,10 @@ extension AppViewModel {
                             // usable channels without capacity).
                             // Fall back to onchain and validate onchain balance immediately.
                             let onchainBalance = lightningService.balances?.spendableOnchainBalanceSats ?? 0
-                            guard validateOnchainBalance(invoiceAmount: invoice.amountSatoshis, onchainBalance: onchainBalance) else {
+                            guard validateOnchainBalance(
+                                invoiceAmount: requestedAmount ?? invoice.amountSatoshis,
+                                onchainBalance: onchainBalance
+                            ) else {
                                 return
                             }
 
@@ -544,7 +548,10 @@ extension AppViewModel {
             // If node is running, validate balance immediately
             if lightningService.status?.isRunning == true {
                 let onchainBalance = lightningService.balances?.spendableOnchainBalanceSats ?? 0
-                guard validateOnchainBalance(invoiceAmount: invoice.amountSatoshis, onchainBalance: onchainBalance) else {
+                guard validateOnchainBalance(
+                    invoiceAmount: requestedAmount ?? invoice.amountSatoshis,
+                    onchainBalance: onchainBalance
+                ) else {
                     return
                 }
             }
@@ -575,20 +582,21 @@ extension AppViewModel {
 
             // If node is running, we can check for channels and validate immediately
             if lightningService.status?.isRunning == true {
+                let paymentAmount = requestedAmount ?? invoice.amountSatoshis
                 // If user has no channels at all, they can never pay a pure lightning invoice.
                 // Show insufficient spending toast and do not navigate to the send flow.
                 let hasAnyChannels = (lightningService.channels?.isEmpty == false)
                 if !hasAnyChannels {
                     let spendingBalance = lightningService.balances?.totalLightningBalanceSats ?? 0
-                    showInsufficientSpendingToast(invoiceAmount: invoice.amountSatoshis, spendingBalance: spendingBalance)
+                    showInsufficientSpendingToast(invoiceAmount: paymentAmount, spendingBalance: spendingBalance)
                     return
                 }
 
                 // If channels are usable, validate capacity immediately
                 if let channels = lightningService.channels, channels.contains(where: \.isUsable) {
-                    guard lightningService.canSend(amountSats: invoice.amountSatoshis) else {
+                    guard lightningService.canSend(amountSats: paymentAmount) else {
                         let spendingBalance = lightningService.balances?.totalLightningBalanceSats ?? 0
-                        showInsufficientSpendingToast(invoiceAmount: invoice.amountSatoshis, spendingBalance: spendingBalance)
+                        showInsufficientSpendingToast(invoiceAmount: paymentAmount, spendingBalance: spendingBalance)
                         return
                     }
                 }

changelog.d/next/684.fixed.md

@@ -0,0 +1 @@
+Contact payments now ignore malformed receiver markers from other contacts and show the correct insufficient-balance error for unaffordable payment requests.