refactor(apple): type the merged relay/network resources

Convert master's raw-string localization keys and SF Symbols in the new
relay/network code to typed accessors, matching this branch's typed-resources
convention: relay mode labels/descriptions, NetworkSettings strings, the endpoint
id and relay-validation messages (now typed L10n functions), and SF Symbols via
SFSafeSymbols. Retype the model's relayApplyErrorKey from a raw String key to
String.LocalizationValue so no loose key literals remain in the settings layer.

apple/VniDrop/Features/Send/TransferDetailsView.swift

@@ -303,9 +303,9 @@ struct TransferSharePanel: View {
 				image.interpolation(.none).resizable().scaledToFit().padding(14)
 			} else {
 				VStack(spacing: 10) {
-					Image(systemName: "qrcode")
+					Image(systemSymbol: .qrcode)
 						.font(.system(size: 36, weight: .medium))
-					Text(LocalizedStringKey("transfer_qr_unavailable"))
+					Text(String(localized: L10n.Transfer.qrUnavailable))
 						.font(VniType.bodySmall)
 						.multilineTextAlignment(.center)
 				}