- Defer LOAD_GAME dispatch until SimBridge reaches CONNECTED (critical)
- Guard _build_saves_list() against queue_free() race on rapid reopen
- Disable save entries with empty newest_save, guard in _on_save_selected
- Send before show_loading on F6 quickload, skip overlay on send failure
- Clear pending_load_path in _on_new_game()/_on_continue() (stale path)
- Add hide_loading(success: bool) API for future failure-state UI
- Add test_save_load_flow_sprint21.gd covering LoadingScreen + GameState
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
#257: Add Load Game screen to main menu with sorted save list, loading
overlay during quickload round-trip, and pending_load_path cross-scene
flow. F5/F6 quicksave/quickload were already wired.
#561: Move debug_overlay.gd from scripts/ui/ to ui/ for consistency
with all other UI components. Update scene and test references.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>