docs: v2.2.0 — script source tinting, scroll fix, output log
Add v2.2.0 documentation across Changelog, User-Guide, and Settings:
- Script source button tinting (warm/cool; Settings → Window checkbox)
- Scroll flicker fix description
- Script Output Log window (≡ Log button, Consolas, syntax highlighting,
completion footers, buffered when closed, dark mode, app icon)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>