feat(apple): contacts screen and consent prompts

Device list, detail, and block list under Settings, plus the two sheets:
an incoming offer and a device asking to be remembered. Both are
answer-only, since swiping away would leave the sender waiting.

Accepting an offer routes the released ticket into the ordinary receive
path, so the platform still chooses the destination. The prompt does not
ask a second time; it only falls back to the review sheet when the
destination is unusable.

apple/VniDrop/App/RootView.swift

@@ -60,6 +60,11 @@ struct RootView: View {
 					approvals: graph.approvalCoordinator,
 					sendModel: sendModel
 				)
+				ContactPromptLayer(
+					contacts: graph.contactsModel,
+					receiveModel: receiveModel,
+					approvals: graph.approvalCoordinator
+				)
 				// Top-most so the toast is never covered by the approval overlay's
 				// full-bleed clear layer. Observes the live `graph.messages` directly.
 				SnackbarHost(controller: graph.messages)
@@ -167,7 +172,8 @@ struct RootView: View {
 		switch destination {
 		case .send: SendScreen(model: sendModel, windowClass: windowClass)
 		case .receive: ReceiveScreen(model: receiveModel, windowClass: windowClass)
-		case .settings: SettingsScreen(model: settingsModel, windowClass: windowClass)
+		case .settings:
+			SettingsScreen(model: settingsModel, contacts: graph.contactsModel, windowClass: windowClass)
 		}
 	}
 
@@ -283,3 +289,49 @@ import UIKit
 #else
 import AppKit
 #endif
+
+/// Hosts the device-history consent prompts, alongside `ApprovalLayer`.
+///
+/// Separate from the approval layer because the two never compete: an approval
+/// belongs to a transfer this device is sending, and these belong to a device
+/// asking to reach it. Both are suppressed while the other is up so the user is
+/// never answering two modals at once.
+private struct ContactPromptLayer: View {
+	@ObservedObject var contacts: ContactsModel
+	let receiveModel: ReceiveModel
+	@ObservedObject var approvals: ApprovalCoordinator
+
+	@State private var showPrompt = false
+
+	var body: some View {
+		ContactPromptHost(
+			isPresented: $showPrompt,
+			state: contacts.state,
+			onPairingResponse: { endpointId, accepted in
+				Task { await contacts.respondToPairing(endpointId: endpointId, accepted: accepted) }
+			},
+			onOfferResponse: { offerId, accepted in
+				Task {
+					// The ticket is released only on acceptance; the receive then
+					// runs through the ordinary path so the platform picks the
+					// destination.
+					if let ticket = await contacts.respondToOffer(offerId: offerId, accepted: accepted) {
+						receiveModel.receiveOffered(ticket: ticket)
+					}
+				}
+			}
+		)
+		.onChange(of: promptKey) { _, key in
+			showPrompt = key != nil
+		}
+	}
+
+	/// One identity for "is there something to answer", so an offer replacing a
+	/// pairing prompt re-presents rather than silently swapping content.
+	private var promptKey: String? {
+		guard approvals.state.current == nil else { return nil }
+		if let offer = contacts.state.currentOffer { return "offer-\(offer.offerId)" }
+		if let pairing = contacts.state.currentPairing { return "pairing-\(pairing.endpointId)" }
+		return nil
+	}
+}