feat(ios): replace embedded website with initial native SwiftUI API client

Introduce real SwiftUI auth/dashboard/task/note/shopping screens, a bounded origin-bound URLSession transport and Keychain-backed native sessions. Archive the rejected WebKit renderer rather than embedding it for unfinished modules. Sixteen portable URL/contract/transport tests and Swift format/parsing pass on Linux; Apple SDK application and UI validation remains mandatory. This is an incomplete native slice, not full PWA parity or a release.

ios/Sources/YuvomiApp.swift

@@ -3,6 +3,6 @@ import SwiftUI
 @main
 struct YuvomiApp: App {
     var body: some Scene {
-        WindowGroup { ContentView() }
+        WindowGroup { NativeRootView() }
     }
 }