Adds --ai flag that sends the directory tree, file categories, and
sampled file contents to Claude for analysis. Produces a brief
summary at the top of the report and a detailed breakdown at the
end. Requires ANTHROPIC_API_KEY env var; degrades gracefully without it.
Uses only stdlib (urllib) to keep the zero-dependency constraint.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
