Scaffold macos-swift: native SwiftUI/AppKit client for traverse-starter

[enricopiovesan]

Summary

Create apps/traverse-starter/macos-swift/ — a native macOS client for the traverse-starter reference app using SwiftUI. Phase 1 uses the same HTTP polling approach as web-react. Shares TraverseClient.swift with ios-swift (copy or Swift package — see #58). SSE is the phase 2 upgrade path.

Phase 1 scope (HTTP polling — unblocked)

• Native macOS app calling the Traverse HTTP/JSON API
• Text input → POST /v1/workspaces/{workspace}/execute → poll → render result
• Runtime URL + workspace configurable via Preferences window (⌘,)
• Health check status in toolbar
• macOS UI conventions: menu bar, keyboard shortcuts (⌘↵ submit, ⌘R reset), window management

Stack

Concern	Choice
Language	Swift 6
UI framework	SwiftUI (AppKit bridge for menu bar)
HTTP	URLSession
Min target	macOS 14
Architecture	MVVM — ExecutionViewModel owns idle→loading→polling→done state

Directory structure

apps/traverse-starter/macos-swift/
  TraverseStarterMac.xcodeproj/
  TraverseStarterMac/
    TraverseClient.swift          # URLSession HTTP client (shared with ios-swift)
    ExecutionViewModel.swift      # ObservableObject — idle/loading/polling/done
    ContentView.swift             # Main view
    PreferencesView.swift         # Runtime URL + workspace (⌘,)
    AppDelegate.swift             # NSApplicationDelegate, menu bar
    Assets.xcassets/
    Info.plist
  TraverseStarterMacTests/

Phase 2 upgrade path (do not implement now)

When Traverse ships #525 / #526 / #527:

• Replace polling with SSE subscription (URLSessionDataDelegate)
• Replace execute() with sendCommand("submit", { note })
• Extract shared TraverseCore Swift package with ios-swift (see Extract TraverseCore Swift package shared between ios-swift and macos-swift #58)

Definition of Done

• Xcode project builds for macOS 14+ with zero warnings
• Preferences window: manual URL + workspace, persisted to UserDefaults
• Health check status in toolbar
• Note input → execute → poll → renders output fields
• ⌘↵ submits, ⌘R resets
• Unit tests for TraverseClient and ExecutionViewModel
• README in macos-swift/ covering: prerequisites, runtime URL config, build and run
• scripts/ci/repository_checks.sh updated to acknowledge macos-swift/ directory

[enricopiovesan]

Design language reference: docs/design-language.md (added in #74 / #60). Platform client DOD should follow the three-zone IA and field naming there.

[enricopiovesan]

Closing: platform client shipped and Project 2 marked Done. Issue left open in error after merge. Stale references in README/design-language tracked in #83.