feat: add native local location capture (#4)

Add explicit permission handling, independent continuous and single capture,
location status and deterministic CI coverage.

Final decisions and validation:
https://github.com/jayanezj/traccar-client-macos/issues/4#issuecomment-6399189792

TraccarClient/Interface/LocationStatusView.swift

@@ -0,0 +1,53 @@
+import SwiftUI
+
+struct LocationStatusView: View {
+    let location: LocationModel
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 16) {
+            Label("Location capture", systemImage: "location")
+                .font(.title2)
+            Text("Capture your Mac's location continuously or once while paused. Nothing is sent to a server.")
+            Text("Choose Start or Capture once to allow macOS to request location permission if needed.")
+                .foregroundStyle(.secondary)
+            Form {
+                LabeledContent("Continuous capture", value: location.continuousRequested ? "Active" : "Paused")
+                LabeledContent("Condition", value: location.status)
+                LabeledContent("Location Services", value: location.availability.services.rawValue)
+                LabeledContent("Permission", value: location.availability.permission.rawValue)
+                LabeledContent("Single capture", value: location.singleStatus.rawValue)
+                if let fix = location.lastFix {
+                    LabeledContent("Fix timestamp", value: fix.timestamp.formatted(date: .numeric, time: .standard))
+                    LabeledContent("Reported accuracy", value: "\(fix.horizontalAccuracy.formatted()) m")
+                    LabeledContent("Source", value: location.lastFixOrigin?.rawValue ?? "Location Services")
+                } else {
+                    Text("No location received.").foregroundStyle(.secondary)
+                }
+            }
+            .formStyle(.grouped)
+            if let error = location.errorMessage ?? location.continuousError {
+                Label(error, systemImage: "exclamationmark.triangle")
+                    .foregroundStyle(.orange)
+            }
+            HStack {
+                Button(location.continuousRequested ? "Pause" : "Start") {
+                    if location.continuousRequested { location.pause() } else {
+                        location.startContinuous()
+                    }
+                }
+                Button("Capture once") {
+                    location.captureOnce()
+                }
+                .disabled(location.singleStatus == .waiting)
+                if location.singleStatus == .waiting {
+                    Button("Cancel capture") { location.cancelSingle() }
+                }
+                Spacer()
+                Button("Refresh status") { location.refreshAvailability() }
+            }
+        }
+        .padding(20)
+        .frame(width: 620, height: 540)
+        .onAppear { location.refreshAvailability() }
+    }
+}