Remove dead onboarding code: Hatch/, Interview/, and unused step views

clients/macos/vellum-assistant/Features/MainWindow/UserProfile.swift

@@ -0,0 +1,14 @@
+import Foundation
+
+/// Lightweight representation of the user profile stored in UserDefaults
+/// under the `"user.profile"` key. Originally populated by the onboarding
+/// interview's profile-extraction step.
+struct UserProfile: Codable, Sendable {
+    let name: String?
+    let role: String?
+    let goals: [String]?
+    let painPoints: [String]?
+    let communicationStyle: String?
+    let interests: [String]?
+    let personality: String?
+}