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

GasTankAR/Domain/Leads/Lead.swift

@@ -0,0 +1,36 @@
+import Foundation
+
+struct Lead: Identifiable, Equatable, Sendable {
+    let id: String
+    let companyName: String?
+    let contact: LeadContact?
+    let address: LeadAddress
+    let phoneNumber: String?
+    let createdAt: Date
+    let offerCount: Int
+    let unsignedContractCount: Int
+    var isBookmarked: Bool
+}
+
+struct LeadContact: Equatable, Sendable {
+    let title: String?
+    let firstName: String
+    let lastName: String
+}
+
+struct LeadAddress: Equatable, Sendable {
+    let street: String?
+    let postalCode: String
+    let city: String
+}
+
+enum LeadError: Error, Equatable, Sendable {
+    case offline
+    case timeout
+    case serviceUnavailable
+    case unauthorized
+    case forbidden
+    case notFound(leadID: String)
+    case invalidResponse
+    case unexpected
+}