Widget links maps:// directly so CarPlay can route to Apple Maps

- The widget now uses the native maps://?daddr= scheme for taps in both
  sizes. In CarPlay there is no containing app to relay through, but since
  Apple Maps IS a CarPlay app, the system may route the tap straight to
  Maps on the car display (WWDC25: widgets can launch apps in CarPlay).
- iOS keeps working via onOpenURL: the app now forwards maps:// URLs (if
  the Home Screen delivers them to the app), plus legacy fuelboard:// and
  http://maps.apple.com links from older cached timelines.
- No public API exists for a widget to detect CarPlay context, so the
  single maps:// link serves both; the app-side forward is the iOS safety
  net. 35 tests pass.

FuelBoard/FuelBoardApp.swift

@@ -9,18 +9,35 @@ struct FuelBoardApp: App {
         }
     }
 
-    /// WidgetKit widgets can only open their containing app, so a widget tap
-    /// delivers a `fuelboard://directions?lat=..&lng=..` URL here instead of
-    /// opening Apple Maps itself. Forward it to the native Maps directions
-    /// URL (`maps://?daddr=`), which is what the app's own rows use.
+    /// Handles deep links that end up in the app. Widget taps arrive here in
+    /// two cases:
+    ///   - legacy/cached widget timelines using the `fuelboard://` relay, or
+    ///   - the Home Screen delivering a `maps://` URL to the containing app
+    ///     instead of opening Maps directly (the system's choice on iOS).
+    /// Either way we forward to the native Apple Maps directions URL. The
+    /// `http://maps.apple.com` form is also handled, from very old timelines.
+    /// In CarPlay the widget uses the same `maps://` URL, which routes to
+    /// Apple Maps without ever launching this app.
     private func handleOpenURL(_ url: URL) {
-        guard url.scheme == "fuelboard",
-              url.host == "directions",
-              let components = URLComponents(url: url, resolvingAgainstBaseURL: false),
-              let lat = components.queryItems?.first(where: { $0.name == "lat" })?.value.flatMap(Double.init),
-              let lng = components.queryItems?.first(where: { $0.name == "lng" })?.value.flatMap(Double.init),
-              let mapsURL = URL(string: "maps://?daddr=\(lat),\(lng)&t=d")
+        guard let components = URLComponents(url: url, resolvingAgainstBaseURL: false),
+              let items = components.queryItems
         else { return }
+
+        // Preferred: maps://?daddr=lat,lng&t=d (also covers http://maps.apple.com).
+        if let daddr = items.first(where: { $0.name == "daddr" })?.value {
+            openMaps(daddr: daddr)
+            return
+        }
+
+        // Legacy relay: fuelboard://directions?lat=..&lng=..
+        if let lat = items.first(where: { $0.name == "lat" })?.value.flatMap(Double.init),
+           let lng = items.first(where: { $0.name == "lng" })?.value.flatMap(Double.init) {
+            openMaps(daddr: "\(lat),\(lng)")
+        }
+    }
+
+    private func openMaps(daddr: String) {
+        guard let mapsURL = URL(string: "maps://?daddr=\(daddr)&t=d") else { return }
         UIApplication.shared.open(mapsURL)
     }
 }