Onboarding: network page no longer loads data — bare TCP connect

- The Data page's probe was an HTTP GET /api/v1/stations (8s timeout)
  that read as 'loading data' and could stall the slide. Replaced with a
  bare TCP connect to the relay host:port — just enough to trigger the
  iOS Local Network permission prompt, zero payload transferred.
- Grant -> auto-advance to the final slide (existing onChange); denial or
  unreachable relay -> Continue re-enables and proceeds. 12s safety
  timeout so the page can never dead-end on a spinner.
- NWConnection held on the prompter so the connect survives until the
  prompt is answered. Status copy: 'Waiting for network permission…'.
  Full dataset still downloads AFTER onboarding via forced refresh.
  35 tests pass.

FuelBoard/OnboardingView.swift

@@ -1,6 +1,7 @@
 import SwiftUI
 import CoreLocation
 import UserNotifications
+import Network
 
 /// First-launch onboarding: introduces FuelBoard, then walks the user through
 /// the three system permissions (location, notifications, local network for
@@ -201,7 +202,7 @@ struct OnboardingView: View {
         if prompter.dataLoading {
             VStack(spacing: 10) {
                 ProgressView()
-                Text("Checking the FuelBoard Relay…")
+                Text("Waiting for network permission…")
                     .font(.footnote)
                     .foregroundStyle(.secondary)
             }
@@ -282,7 +283,7 @@ struct OnboardingView: View {
                 }
             }
         case 3:
-            primaryButton(prompter.dataLoading ? "Checking…" : "Continue") {
+            primaryButton(prompter.dataLoading ? "Waiting…" : "Continue") {
                 if prompter.dataGranted || prompter.dataDenied {
                     // Prompt answered (allowed or denied) — move on to the
                     // final slide. Never dead-end on an Open Settings button.
@@ -367,6 +368,10 @@ final class OnboardingPermissionPrompter: NSObject, ObservableObject, @preconcur
     @Published private(set) var dataDenied = false
     @Published private(set) var dataLoading = false
 
+    /// Held while the Local Network permission prompt is pending — keeps the
+    /// bare TCP connect alive until the user answers (nil after resolve).
+    private var dataConnection: NWConnection?
+
     private let manager = CLLocationManager()
 
     override init() {
@@ -407,42 +412,64 @@ final class OnboardingPermissionPrompter: NSObject, ObservableObject, @preconcur
         }
     }
 
-    /// Probes the FuelBoard Relay. The first connection to a local-network
+    /// Triggers the Local Network permission prompt WITHOUT loading any data.
-    /// address is what makes iOS show the Local Network permission prompt —
+    /// iOS shows the prompt on the first attempt to reach a local-network
-    /// so this both triggers the prompt in context and verifies data will
+    /// address, so a bare TCP connect to the relay host:port is enough — no
-    /// actually load. A small request (limit 1) is enough; the full download
+    /// HTTP request, no payload, nothing to wait on. Once the user answers
-    /// happens after onboarding completes.
+    /// the prompt the connect either succeeds (granted) or fails (denied);
+    /// either way onboarding proceeds. The full dataset download happens
+    /// AFTER onboarding completes (ContentView's forced refresh).
     func requestDataAccess() {
         guard !dataLoading else { return }
         dataLoading = true
         dataDenied = false
-        Task {
+        let baseURL = RelayFuelProvider().baseURL
-            var ok = false
+        guard let host = baseURL.host,
-            defer {
+              let port = baseURL.port else {
             dataLoading = false
-                dataGranted = ok
+            dataDenied = true
-                dataDenied = !ok
+            return
         }
-            do {
+        let connection = NWConnection(
-                var components = URLComponents(
+            host: NWEndpoint.Host(host),
-                    url: RelayFuelProvider().baseURL.appendingPathComponent("api/v1/stations"),
+            port: NWEndpoint.Port(rawValue: UInt16(port))!,
-                    resolvingAgainstBaseURL: false
+            using: .tcp
-                )!
+        )
-                components.queryItems = [
+        dataConnection = connection
-                    URLQueryItem(name: "fuel", value: FuelType.e10.rawValue),
+        connection.stateUpdateHandler = { [weak self] state in
-                    URLQueryItem(name: "limit", value: "1"),
+            Task { @MainActor in
-                ]
+                guard let self else { return }
-                var request = URLRequest(url: components.url!)
+                switch state {
-                request.timeoutInterval = 8
+                case .ready:
-                let (_, response) = try await URLSession.shared.data(for: request)
+                    // Connect succeeded — local network allowed.
-                guard let http = response as? HTTPURLResponse, http.statusCode == 200 else {
+                    self.dataConnection = nil
-                    throw FuelProviderError.relayUnavailable
+                    self.dataLoading = false
+                    self.dataGranted = true
+                    self.dataDenied = false
+                case .failed, .cancelled:
+                    // Connect failed (denied, or relay unreachable). Either
+                    // way we do NOT dead-end: onboarding continues.
+                    self.dataConnection = nil
+                    self.dataLoading = false
+                    self.dataGranted = false
+                    self.dataDenied = true
+                default:
+                    break // .preparing / .waiting — prompt pending, hold on
                 }
-                ok = true
-            } catch {
-                ok = false
             }
         }
+        connection.start(queue: .main)
+        // Safety timeout: if the prompt is ignored or the connect stalls, drop
+        // back to the enabled Continue button instead of an endless spinner.
+        Task { @MainActor [weak self] in
+            try? await Task.sleep(nanoseconds: 12_000_000_000)
+            guard let self, self.dataLoading else { return }
+            self.dataLoading = false
+            self.dataGranted = false
+            self.dataDenied = true
+            self.dataConnection = nil
+            connection.cancel()
+        }
     }
 
     nonisolated func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {