- Add GET /api/system/browse-dir and POST /api/system/create-dir endpoints
- Add Folder Browser Modal overlay in index.html
- Add browse buttons to both job-specific and default setting temp dir inputs
- Add JS helpers and event handlers for directory list loading, parent navigation, directory selection, and new folder creation
- Add settings.json persistence (load/save) in backend
- Add GET/POST /api/settings endpoints for default_temp_dir
- Add Default Temp Directory config UI in Temporary Storage section
- Auto-fallback: jobs use saved default if no per-job temp_dir set
- Per-job Advanced Options placeholder syncs with saved default
- Add settings.json to .gitignore for per-machine config
david