Verifies the site: builds it in memory and runs every check rule.

Usage

mix cherry.check [--source DIR] [--strict] [--drafts] [--future] [--json]

Rules: broken internal links, missing descriptions, images without alt text, duplicate titles, Atom feed sanity. Errors exit 1; --strict promotes warnings to errors. Diagnostics are structured (file, rule, message, severity) — this is the agent's verifier loop: build → check → fix → repeat.