Refactor interactively with astcount

Use astcount to find structural simplifications, but make the user an active partner in consequential decisions. Do not turn “interactive” into vague status questions: inspect first, present concrete options and evidence, and ask focused questions about real tradeoffs.

Establish the measurement together

Infer the scope from the request. Resolve one astcount command, run it with --version, and reuse that exact invocation:

1. When command -v nix succeeds, use nix run github:wokalski/astcount/v0.3.0 --.
2. Otherwise, use bunx astcount@0.3.0 when Bun is available.
3. Otherwise, use npx --yes astcount@0.3.0 when npx is available.
4. Stop if none is available.