Promote the Unreleased changelog block to 8.2.0, bump the package
version in pyproject.toml and uv.lock, refresh the stale CITATION.cff
version (8.0.0 -> 8.2.0), and update the `--version` example in
docs/cli.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hp2ggSU99VNQ8heHKvX7Pb