Add scan flow MVP and local Axiom skill workspace

This snapshot establishes the camera-to-result recognition flow and related tests while checking in the project skill/docs assets required for the configured local tooling.

StackDex/Views/CameraPreviewView.swift

@@ -0,0 +1,28 @@
+import AVFoundation
+import SwiftUI
+
+struct CameraPreviewView: UIViewRepresentable {
+    let session: AVCaptureSession
+
+    func makeUIView(context: Context) -> PreviewView {
+        let view = PreviewView()
+        view.previewLayer.session = session
+        view.previewLayer.videoGravity = .resizeAspectFill
+        return view
+    }
+
+    func updateUIView(_ uiView: PreviewView, context: Context) {
+        uiView.previewLayer.session = session
+    }
+}
+
+final class PreviewView: UIView {
+    override class var layerClass: AnyClass { AVCaptureVideoPreviewLayer.self }
+
+    var previewLayer: AVCaptureVideoPreviewLayer {
+        guard let layer = layer as? AVCaptureVideoPreviewLayer else {
+            fatalError("PreviewView requires AVCaptureVideoPreviewLayer.")
+        }
+        return layer
+    }
+}