fix: stop the device picker hanging on an offer

Two causes. The connect step had no timeout, so an unreachable device was
retried indefinitely instead of falling through to hold-for-later; it now
gives up after 15s and holds the offer as designed.

The picker also waited on the whole exchange, which includes a person on the
other device deciding — up to two minutes. It now closes on tap and reports
the outcome as a message, and a decline or an unanswered offer is shown as
information rather than an error, since the offer did arrive.

apple/VniDrop/UI/Feedback/UserFacingError.swift

@@ -3,6 +3,12 @@ import VnidropCore
 
 /// Maps technical failures to stable, user-facing catalog keys. Ported from
 /// `ui/feedback/UserFacingError.kt`. Never exposes raw `reason=` blobs.
+/// How an offered transfer ended without being accepted.
+enum OfferRefusal {
+	case declined
+	case noAnswer
+}
+
 extension Error {
 	func toUiText() -> UiText {
 		if let invitation = self as? InvitationError {
@@ -57,6 +63,19 @@ extension Error {
 			|| haystack.contains("user canceled")
 	}
 
+	/// The other device answered, and the answer was no.
+	///
+	/// Not a failure of this device: the offer was delivered and a person
+	/// declined it, so it is reported as information rather than an error.
+	var offerRefusal: OfferRefusal? {
+		let haystack = technicalDetail.lowercased()
+		if haystack.contains("receiver-declined") || haystack.contains("declined-recently") {
+			return .declined
+		}
+		if haystack.contains("no-response") { return .noAnswer }
+		return nil
+	}
+
 	/// Prefers a `VnidropError` reason; else the localized description.
 	var technicalDetail: String {
 		if let vni = self as? VnidropError {