chore: scaffold Voice iOS app (Phase 0)

XcodeGen project, SwiftUI iOS 17 target dev.shane.voice, SPM
livekit-client-swift 2.16.0, mic usage + ATS LAN exception in
Info.plist, placeholder conversation screen and Settings with
server URL field.

Sources/Features/Settings/SettingsView.swift

@@ -0,0 +1,28 @@
+import SwiftUI
+
+struct SettingsView: View {
+    @ObservedObject var settings: SettingsStore
+    @State private var urlText: String = ""
+
+    var body: some View {
+        Form {
+            Section("Server") {
+                TextField("https://192.168.86.2:9178", text: $urlText)
+                    .keyboardType(.URL)
+                    .autocorrectionDisabled()
+                    .onAppear { urlText = settings.serverURL }
+                    .onChange(of: urlText) { _, newValue in
+                        settings.serverURL = newValue
+                    }
+            }
+            Section("Interaction") {
+                Toggle("Text mode", isOn: $settings.textMode)
+            }
+        }
+        .navigationTitle("Settings")
+    }
+}
+
+#Preview {
+    SettingsView(settings: SettingsStore())
+}