v1.1.0

Add Settings dialog for Anthropic API key management

- config.py: read/write ~/.worklog/config.json for persistent settings
- ui/settings_dialog.py: masked key entry with show/hide toggle, live
  status indicator, saves key to config and applies to os.environ immediately
- topbar: ⚙ Settings button opens the dialog
- main.py: loads stored API key from config on startup
- ai_summary.py: error message now points to Settings instead of env var

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>