Add lead workflows, PDF signing, AR projects and photo gallery integration

GasTankAR/Views/Leads/Shared/LeadDocumentPreview.swift

@@ -0,0 +1,52 @@
+import SwiftUI
+import QuickLook
+
+/// Native full-screen PDF reading, including zoom, page navigation and system open-in actions.
+struct LeadDocumentPreview: View {
+    let url: URL
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        NavigationStack {
+            LeadQuickLookView(url: url)
+                .navigationBarTitleDisplayMode(.inline)
+                .toolbar {
+                    ToolbarItem(placement: .confirmationAction) {
+                        Button(role: .confirm) { dismiss() }
+                            .labelStyle(.iconOnly)
+                            .accessibilityLabel("Zurück zur Unterschrift")
+                    }
+                }
+        }
+    }
+}
+
+private struct LeadQuickLookView: UIViewControllerRepresentable {
+    let url: URL
+
+    func makeUIViewController(context: Context) -> QLPreviewController {
+        let controller = QLPreviewController()
+        controller.dataSource = context.coordinator
+        return controller
+    }
+
+    func updateUIViewController(_ controller: QLPreviewController, context: Context) {
+        guard context.coordinator.url != url else { return }
+        context.coordinator.url = url
+        controller.reloadData()
+    }
+
+    func makeCoordinator() -> Coordinator { Coordinator(url: url) }
+
+    final class Coordinator: NSObject, QLPreviewControllerDataSource {
+        var url: URL
+
+        init(url: URL) { self.url = url }
+
+        func numberOfPreviewItems(in controller: QLPreviewController) -> Int { 1 }
+
+        func previewController(_ controller: QLPreviewController, previewItemAt index: Int) -> any QLPreviewItem {
+            url as NSURL
+        }
+    }
+}