feat(apple): notify the sender when a receiver's delivery fails

plannedReceiverNotifications only fired for completed receivers, so a failed
delivery produced no notification. Add a receiverFailed kind wired through the
planner, id, and deliver paths, with localized notifications_receiver_failed_*
strings and a unit test.

apple/Tests/TransferNotificationTests.swift

@@ -41,4 +41,11 @@ final class TransferNotificationTests: XCTestCase {
 		let requests = [Fixtures.request(id: "a", requestedAt: 1, status: .completed)]
 		XCTAssertTrue(plannedReceiverNotifications(requests, published: ["receiver-completed-a"]).isEmpty)
 	}
+
+	func testReceiverNotificationsFireForFailedReceivers() {
+		let requests = [Fixtures.request(id: "x", requestedAt: 1, status: .failed)]
+		let planned = plannedReceiverNotifications(requests, published: [])
+		XCTAssertEqual(planned.map(\.id), ["receiver-failed-x"])
+		XCTAssertEqual(planned.first?.kind, .receiverFailed)
+	}
 }

apple/VniDrop/Features/Notifications/TransferNotificationCoordinator.swift

@@ -7,6 +7,7 @@ enum TransferNotificationKind: Equatable {
 	case receiveCompleted    // An incoming transfer finished downloading.
 	case receiveFailed       // An incoming transfer failed.
 	case receiverCompleted   // A receiver finished downloading your shared transfer.
+	case receiverFailed      // A receiver's download of your shared transfer failed.
 }
 
 /// A notification resolved from core state but not yet published. `transferName`
@@ -39,11 +40,17 @@ func plannedTransferNotifications(_ transfers: [Transfer], published: Set<String
 /// transfer, excluding already-published ids.
 func plannedReceiverNotifications(_ requests: [ReceiverRequestModel], published: Set<String>) -> [PlannedNotification] {
 	requests.compactMap { request in
-		guard request.status == .completed else { return nil }
+		let kind: TransferNotificationKind
-		let id = "receiver-completed-\(request.id)"
+		let idPrefix: String
+		switch request.status {
+		case .completed: kind = .receiverCompleted; idPrefix = "receiver-completed"
+		case .failed: kind = .receiverFailed; idPrefix = "receiver-failed"
+		default: return nil
+		}
+		let id = "\(idPrefix)-\(request.id)"
 		guard !published.contains(id) else { return nil }
 		return PlannedNotification(
-			id: id, kind: .receiverCompleted,
+			id: id, kind: kind,
 			transferName: request.transferName,
 			receiver: request.receiverName ?? request.receiverDeviceName
 		)
@@ -56,6 +63,7 @@ private func transferNotificationId(_ kind: TransferNotificationKind, transferId
 	case .receiveCompleted: return "receive-completed-\(transferId)"
 	case .receiveFailed: return "receive-failed-\(transferId)"
 	case .receiverCompleted: return "receiver-completed-\(transferId)"
+	case .receiverFailed: return "receiver-failed-\(transferId)"
 	}
 }
 
@@ -176,6 +184,12 @@ final class TransferNotificationCoordinator: ObservableObject {
 				id: plan.id,
 				title: String(localized: L10n.Notifications.receiverCompletedTitle),
 				body: L10n.Notifications.receiverCompletedBody(receiver: receiver, transferName: name))
+		case .receiverFailed:
+			let receiver = plan.receiver ?? String(localized: L10n.Approval.nearbyDevice)
+			notification = LocalNotification(
+				id: plan.id,
+				title: String(localized: L10n.Notifications.receiverFailedTitle),
+				body: L10n.Notifications.receiverFailedBody(receiver: receiver, transferName: name))
 		}
 		if case .failure(let error) = await notifications.publish(notification) {
 			messages.error(error)

localization/strings.json

@@ -1948,6 +1948,50 @@
         "ru": "Передача получена"
       }
     },
+    "notifications_receiver_failed_body": {
+      "context": "Notification body shown to the sender when a receiver's download fails. {receiver} = receiver name, {transferName} = transfer name.",
+      "targets": [
+        "apple"
+      ],
+      "args": [
+        {
+          "name": "receiver",
+          "type": "string"
+        },
+        {
+          "name": "transferName",
+          "type": "string"
+        }
+      ],
+      "translations": {
+        "en": "{receiver} couldn't receive “{transferName}”",
+        "fr": "{receiver} n'a pas pu recevoir « {transferName} »",
+        "es": "{receiver} no pudo recibir «{transferName}»",
+        "it": "{receiver} non ha potuto ricevere “{transferName}”",
+        "de": "{receiver} konnte „{transferName}“ nicht empfangen",
+        "pt": "{receiver} não conseguiu receber “{transferName}”",
+        "pl": "{receiver} nie mógł odebrać „{transferName}”",
+        "nl": "{receiver} kon “{transferName}” niet ontvangen",
+        "ru": "{receiver} не удалось получить «{transferName}»"
+      }
+    },
+    "notifications_receiver_failed_title": {
+      "context": "Notification title shown to the sender when a receiver's download fails.",
+      "targets": [
+        "apple"
+      ],
+      "translations": {
+        "en": "Delivery failed",
+        "fr": "Échec de l'envoi",
+        "es": "Error en la entrega",
+        "it": "Consegna non riuscita",
+        "de": "Übertragung fehlgeschlagen",
+        "pt": "Falha na entrega",
+        "pl": "Dostarczenie nie powiodło się",
+        "nl": "Levering mislukt",
+        "ru": "Ошибка доставки"
+      }
+    },
     "notifications_send_failed_body": {
       "context": "Notification body shown to the sender when a shared transfer fails. {transferName} = transfer name.",
       "targets": [