feat(chat): share SwiftUI chat across macOS+iOS

apps/ios/Sources/Chat/ChatSheet.swift

@@ -0,0 +1,33 @@
+import ClawdisChatUI
+import SwiftUI
+
+struct ChatSheet: View {
+    @Environment(\.dismiss) private var dismiss
+    @StateObject private var viewModel: ClawdisChatViewModel
+
+    init(bridge: BridgeSession, sessionKey: String = "main") {
+        let transport = IOSBridgeChatTransport(bridge: bridge)
+        self._viewModel = StateObject(
+            wrappedValue: ClawdisChatViewModel(
+                sessionKey: sessionKey,
+                transport: transport))
+    }
+
+    var body: some View {
+        NavigationStack {
+            ClawdisChatView(viewModel: self.viewModel)
+                .navigationTitle("Chat")
+                .navigationBarTitleDisplayMode(.inline)
+                .toolbar {
+                    ToolbarItem(placement: .topBarTrailing) {
+                        Button {
+                            self.dismiss()
+                        } label: {
+                            Image(systemName: "xmark")
+                        }
+                        .accessibilityLabel("Close")
+                    }
+                }
+        }
+    }
+}