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

GasTankAR/Services/StubAuthenticationService.swift

@@ -0,0 +1,21 @@
+import Foundation
+
+struct StubAuthenticationService: AuthenticationService {
+    let simulatedError: LoginError?
+    let delay: Duration
+
+    init(simulatedError: LoginError? = nil, delay: Duration = .milliseconds(600)) {
+        self.simulatedError = simulatedError
+        self.delay = delay
+    }
+
+    func signIn(salesCode: String) async throws -> LoginSession {
+        try await Task.sleep(for: delay)
+        try Task.checkCancellation()
+        if let simulatedError {
+            throw simulatedError
+        }
+        // Demo employee until the authentication API supplies the profile.
+        return LoginSession(salesCode: salesCode, displayName: "M. Krämer")
+    }
+}