Settings screen

# All preference types and their default settings:

## General:

- Disable presence:
- [x] After inactivity (10 minutes)
_This will reset elapsed time_
- [ ] If XCode is not frontmost application
- Icons:
- [x] Display file icon
- [x] Use large file icon
- [ ] Display app icon
- Active file/project:
- [x] Display filename
- [x] Display extension
- [x] Display scheme
- [x] Display workspace
- [x] Display elapsed time
_Since active workspace was first loaded._

## Blacklist:

- Ignored workspaces
- Add current (button)
- Ignored projects
- Add current (button)

The issue names no files, tests, or entry points. Start by locating the existing settings and preference-handling code, then use the listed General and Blacklist options as the acceptance checklist, including the two “Add current” actions and their stated defaults.

Written by the indexing model from the issue text.