The README features block grew to 38 bullets plus a full lint-rules
table, making the document hard to scan. This commit:
- Creates FEATURES.md with a structured reference covering lint rules
(GL001–GL043 tables), include resolution, context simulation, output
formats, configuration, graph visualization, and developer tools.
- Replaces the flat bullet list in README with a 6-line "What it does"
category summary that links to FEATURES.md and ROADMAP.md.
- Removes the redundant ## Lint rules section from README (now in
FEATURES.md).
- Adds 'explain' to the commands block in the README Usage section.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>