feat(paykit): implement background Noise server with push notifications and invoice number linking

- Add paykitNoiseRequest notification type to BlocktankNotificationType
- Update FcmService to handle Noise request notifications
- Create NoiseServerWorker for background Noise server operation
- Add startBackgroundServer method to NoisePaymentService
- Create PushNotificationService for sending wake notifications
- Create ReceiptService for managing receipt-request associations
- Add invoiceNumber and receiptId fields to PaymentRequest model
- Add requestId and invoiceNumber to Receipt model
- Add cross-reference methods to PaymentRequestStorage
- Add push notification endpoint publishing to DirectoryService
- Update PaymentRequestsScreen UI to display invoice numbers and linked receipts

Author: JOHN

RELEASE_NOTES.md

@@ -0,0 +1,131 @@
+# Release Notes
+
+## Paykit Integration Release
+
+### Version 1.0.0 - Paykit Edition
+
+**Release Date:** December 2025
+
+---
+
+## What's New
+
+### 🎉 Paykit Integration
+
+Bitkit now supports Paykit, enabling seamless payments with your Pubky identity:
+
+- **Pay Anyone with Pubky**: Send Bitcoin to any Pubky username
+- **Automatic Discovery**: Payment methods are discovered automatically
+- **Secure Sessions**: Connect with Pubky-ring for full functionality
+- **Direct Payments**: Encrypted peer-to-peer payments via Noise Protocol
+
+### Features
+
+#### Session Management
+- Connect Bitkit to your Pubky-ring identity
+- Cross-device authentication via QR code
+- Automatic session refresh
+- Secure session storage in Android Keystore
+
+#### Payment Discovery
+- Automatic lookup of payment methods
+- Support for Lightning, on-chain, and interactive payments
+- Fallback chains when primary method fails
+- Contact-based payments
+
+#### Contacts
+- Sync contacts from your Pubky follows
+- Discover payment-enabled contacts
+- Quick payments to saved contacts
+
+#### Backup & Restore
+- Export sessions and settings
+- Password-protected encryption
+- Cross-device migration support
+
+---
+
+## Improvements
+
+- Enhanced error messages for payment failures
+- Faster Lightning payment execution
+- Improved network resilience
+- Better battery efficiency for background sync
+- Material3 UI updates for Paykit screens
+
+---
+
+## Bug Fixes
+
+- Fixed session expiry not being detected in some cases
+- Fixed rare crash during QR code scanning
+- Fixed memory leak in contact list
+- Fixed incorrect amount display in some locales
+- Fixed state restoration after process death
+
+---
+
+## Technical Details
+
+### New Dependencies
+- pubky-noise 1.0.0
+- paykit-lib 1.0.0
+- paykit-interactive 1.0.0
+
+### Minimum Requirements
+- Android 9.0 (API 28)+
+- Active internet connection
+- Optional: Pubky-ring app for full functionality
+
+### Known Limitations
+- Interactive payments require Pubky-ring
+- Some features limited without active session
+- Background sync requires sufficient battery
+
+---
+
+## Upgrade Notes
+
+### From Previous Versions
+
+1. Update Bitkit to latest version
+2. Wallet data migrates automatically
+3. Connect to Pubky-ring to enable Paykit features
+4. Sync contacts if desired
+
+### New Users
+
+1. Install Bitkit
+2. Create or restore wallet
+3. Install Pubky-ring (recommended)
+4. Connect Paykit in Settings
+
+---
+
+## Documentation
+
+- [User Guide](docs/USER_GUIDE.md)
+- [Setup Guide](docs/PAYKIT_SETUP.md)
+- [Troubleshooting](docs/USER_GUIDE.md#troubleshooting)
+
+---
+
+## Feedback
+
+We'd love to hear from you:
+- In-app: Settings → Help & Support
+- GitHub: Open an issue
+- Community: Join our Telegram/Discord
+
+---
+
+## Contributors
+
+Thanks to everyone who contributed to this release!
+
+---
+
+## Full Changelog
+
+For the complete list of changes, see [CHANGELOG.md](CHANGELOG.md).
+

app/src/main/AndroidManifest.xml

@@ -6,6 +6,12 @@
         <intent>
             <action android:name="android.settings.APPLICATION_DETAILS_SETTINGS" />
         </intent>
+        <!-- Pubky Ring package visibility for Android 11+ -->
+        <package android:name="to.pubky.ring" />
+        <intent>
+            <action android:name="android.intent.action.VIEW" />
+            <data android:scheme="pubkyring" />
+        </intent>
     </queries>
 
     <uses-feature

app/src/main/java/to/bitkit/data/SettingsStore.kt

@@ -83,6 +83,11 @@ data class SettingsData(
     val defaultTransactionSpeed: TransactionSpeed = TransactionSpeed.default(),
     val showEmptyBalanceView: Boolean = true,
     val hasSeenSpendingIntro: Boolean = false,
+    // Profile data (cached locally)
+    val profileName: String = "",
+    val profileBio: String = "",
+    val profileAvatarUrl: String = "",
+    val profilePubkyId: String = "",
     val hasSeenWidgetsIntro: Boolean = false,
     val hasSeenTransferIntro: Boolean = false,
     val hasSeenSavingsIntro: Boolean = false,

app/src/main/java/to/bitkit/fcm/FcmService.kt

@@ -17,6 +17,8 @@ import to.bitkit.env.Env.DERIVATION_NAME
 import to.bitkit.ext.fromBase64
 import to.bitkit.ext.fromHex
 import to.bitkit.models.BlocktankNotificationType
+import to.bitkit.models.BlocktankNotificationType.paykitNoiseRequest
+import to.bitkit.paykit.workers.NoiseServerWorker
 import to.bitkit.repositories.LightningRepo
 import to.bitkit.ui.pushNotification
 import to.bitkit.utils.Crypto
@@ -76,6 +78,12 @@ class FcmService : FirebaseMessagingService() {
     }
 
     private fun handleAsync() {
+        // Check if this is a Noise request - handle separately
+        if (notificationType == paykitNoiseRequest) {
+            handleNoiseRequest()
+            return
+        }
+        
         val work = OneTimeWorkRequestBuilder<WakeNodeWorker>()
             .setInputData(
                 workDataOf(
@@ -88,6 +96,35 @@ class FcmService : FirebaseMessagingService() {
             .beginWith(work)
             .enqueue()
     }
+    
+    /**
+     * Handle incoming Noise protocol request by starting NoiseServerWorker
+     */
+    private fun handleNoiseRequest() {
+        Logger.debug("Handling incoming Noise request notification", context = TAG)
+        
+        // Extract Noise-specific data from payload
+        val fromPubkey = notificationPayload?.get("from_pubkey")?.toString()?.removeSurrounding("\"")
+        val endpointHost = notificationPayload?.get("endpoint_host")?.toString()?.removeSurrounding("\"")
+        val endpointPort = notificationPayload?.get("endpoint_port")?.toString()?.removeSurrounding("\"")?.toIntOrNull() ?: 9000
+        val noisePubkey = notificationPayload?.get("noise_pubkey")?.toString()?.removeSurrounding("\"")
+        
+        val work = OneTimeWorkRequestBuilder<NoiseServerWorker>()
+            .setInputData(
+                workDataOf(
+                    NoiseServerWorker.KEY_FROM_PUBKEY to fromPubkey,
+                    NoiseServerWorker.KEY_ENDPOINT_HOST to endpointHost,
+                    NoiseServerWorker.KEY_ENDPOINT_PORT to endpointPort,
+                    NoiseServerWorker.KEY_NOISE_PUBKEY to noisePubkey,
+                )
+            )
+            .build()
+        
+        WorkManager.getInstance(this)
+            .enqueue(work)
+        
+        Logger.info("Scheduled NoiseServerWorker for incoming request from ${fromPubkey?.take(12)}...", context = TAG)
+    }
 
     private fun handleNow(data: Map<String, String>) {
         Logger.warn("FCM handler not implemented for: $data")

app/src/main/java/to/bitkit/models/BlocktankNotificationType.kt

@@ -15,7 +15,10 @@ enum class BlocktankNotificationType {
     paykitPaymentRequest,
     paykitSubscriptionDue,
     paykitAutoPayExecuted,
-    paykitSubscriptionFailed;
+    paykitSubscriptionFailed,
+    
+    /** Incoming Noise protocol request - wake app to start Noise server */
+    paykitNoiseRequest;
 
     override fun toString(): String = when {
         name.startsWith("paykit") -> "paykit.$name"

app/src/main/java/to/bitkit/paykit/models/PaymentRequest.kt

@@ -27,7 +27,11 @@ data class PaymentRequest(
     val createdAt: Long = System.currentTimeMillis(),
     val expiresAt: Long? = null,
     var status: PaymentRequestStatus = PaymentRequestStatus.PENDING,
-    val direction: RequestDirection
+    val direction: RequestDirection,
+    /** Optional invoice number for cross-referencing with receipts */
+    val invoiceNumber: String? = null,
+    /** ID of the receipt that fulfilled this request (if paid) */
+    var receiptId: String? = null
 ) {
     val counterpartyName: String
         get() {
@@ -38,4 +42,12 @@ data class PaymentRequest(
                 key
             }
         }
+
+    /** Display invoice number - returns invoiceNumber if set, otherwise request id */
+    val displayInvoiceNumber: String
+        get() = invoiceNumber ?: id
+
+    /** Check if this request has been fulfilled */
+    val isFulfilled: Boolean
+        get() = status == PaymentRequestStatus.PAID && receiptId != null
 }

app/src/main/java/to/bitkit/paykit/models/Receipt.kt

@@ -28,7 +28,11 @@ data class Receipt(
     var txId: String? = null,
     var proof: String? = null,
     var proofVerified: Boolean = false,
-    var proofVerifiedAt: Long? = null
+    var proofVerifiedAt: Long? = null,
+    /** ID of the payment request this receipt fulfills (if any) */
+    val requestId: String? = null,
+    /** Invoice number from the original request (for cross-referencing) */
+    val invoiceNumber: String? = null
 ) {
     companion object {
         fun create(
@@ -37,7 +41,9 @@ data class Receipt(
             counterpartyName: String? = null,
             amountSats: Long,
             paymentMethod: String,
-            memo: String? = null
+            memo: String? = null,
+            requestId: String? = null,
+            invoiceNumber: String? = null
         ): Receipt {
             return Receipt(
                 id = UUID.randomUUID().toString(),
@@ -46,7 +52,9 @@ data class Receipt(
                 counterpartyName = counterpartyName,
                 amountSats = amountSats,
                 paymentMethod = paymentMethod,
-                memo = memo
+                memo = memo,
+                requestId = requestId,
+                invoiceNumber = invoiceNumber
             )
         }
     }

app/src/main/java/to/bitkit/paykit/services/DirectoryService.kt

@@ -161,6 +161,88 @@ class DirectoryService @Inject constructor(
         }
     }
 
+    // MARK: - Push Notification Endpoints
+
+    /**
+     * Push endpoint for receiving wake notifications
+     */
+    @kotlinx.serialization.Serializable
+    data class PushNotificationEndpoint(
+        val deviceToken: String,
+        val platform: String,  // "ios" or "android"
+        val noiseHost: String? = null,
+        val noisePort: Int? = null,
+        val noisePubkey: String? = null,
+        val createdAt: Long = System.currentTimeMillis() / 1000
+    )
+
+    /**
+     * Publish our push notification endpoint to the directory.
+     * This allows other users to discover how to wake our device for Noise connections.
+     */
+    suspend fun publishPushNotificationEndpoint(
+        deviceToken: String,
+        platform: String,
+        noiseHost: String? = null,
+        noisePort: Int? = null,
+        noisePubkey: String? = null
+    ) {
+        val transport = authenticatedTransport ?: throw DirectoryError.NotConfigured
+
+        val endpoint = PushNotificationEndpoint(
+            deviceToken = deviceToken,
+            platform = platform,
+            noiseHost = noiseHost,
+            noisePort = noisePort,
+            noisePubkey = noisePubkey
+        )
+
+        val pushPath = "${PAYKIT_PATH_PREFIX}push"
+        val json = kotlinx.serialization.json.Json.encodeToString(endpoint)
+
+        try {
+            pubkyStorage.store(pushPath, json.toByteArray())
+            Logger.info("Published push notification endpoint to directory", context = TAG)
+        } catch (e: Exception) {
+            Logger.error("Failed to publish push endpoint", e, context = TAG)
+            throw DirectoryError.PublishFailed(e.message ?: "Unknown error")
+        }
+    }
+
+    /**
+     * Discover push notification endpoint for a recipient.
+     * Used to send wake notifications before attempting Noise connections.
+     */
+    suspend fun discoverPushNotificationEndpoint(recipientPubkey: String): PushNotificationEndpoint? {
+        val adapter = PubkyUnauthenticatedStorageAdapter(homeserverBaseURL)
+        val pushPath = "${PAYKIT_PATH_PREFIX}push"
+
+        return try {
+            val data = pubkyStorage.retrieve(pushPath, adapter, recipientPubkey) ?: return null
+            val json = String(data)
+            kotlinx.serialization.json.Json.decodeFromString<PushNotificationEndpoint>(json)
+        } catch (e: Exception) {
+            Logger.error("Failed to discover push endpoint for $recipientPubkey", e, context = TAG)
+            null
+        }
+    }
+
+    /**
+     * Remove our push notification endpoint from the directory.
+     */
+    suspend fun removePushNotificationEndpoint() {
+        val transport = authenticatedTransport ?: throw DirectoryError.NotConfigured
+        val pushPath = "${PAYKIT_PATH_PREFIX}push"
+
+        try {
+            pubkyStorage.delete(pushPath)
+            Logger.info("Removed push notification endpoint from directory", context = TAG)
+        } catch (e: Exception) {
+            Logger.error("Failed to remove push endpoint", e, context = TAG)
+            throw DirectoryError.PublishFailed(e.message ?: "Unknown error")
+        }
+    }
+
     /**
      * Discover payment methods for a recipient
      */