fix: ignore stale private paykit recovery markers

Author: ben-kaufman

Bitkit/Services/PrivatePaykitService+Links.swift

@@ -523,6 +523,11 @@ extension PrivatePaykitService {
             return nil
         }
 
+        let now = UInt64(Date().timeIntervalSince1970)
+        guard marker.createdAt >= now || now - marker.createdAt <= Self.recoveryMarkerFreshnessSeconds else {
+            return nil
+        }
+
         let contactKey = [writerPublicKey, readerPublicKey]
             .compactMap(PubkyPublicKeyFormat.normalized)
             .first { state.contacts[$0] != nil }

Bitkit/Services/PrivatePaykitService.swift

@@ -26,6 +26,7 @@ actor PrivatePaykitService {
     static let pendingPublicationRetryDelay: UInt64 = 5_000_000_000
     static let pendingPublicationRetryAttempts = 60
     static let freshLinkInitialPublishDelaySeconds: UInt64 = 8
+    static let recoveryMarkerFreshnessSeconds: UInt64 = 60 * 60
     static let completedLinkRecoveryMarkerGraceSeconds: UInt64 = 5 * 60
     static let privateStorageRootPath = "/pub/paykit/v0/private/"
     static let privateStoragePurgeMaxEntries = 500