* feat: add /code-review skill for automated code quality checks
Adds a Claude Code skill that reviews changes against project standards:
missing tests, dead code, type safety, lint, and CLAUDE.md conventions.
CLAUDE.md now instructs contributors to run /code-review after implementation.
* refactor: move code standards from CLAUDE.md into /code-review skill
Single source of truth for coding conventions (Python style, type safety,
TypeScript style) is now .claude/skills/code-review.md. CLAUDE.md points
to the skill for reading before coding and running after implementation.
* feat: add code comments convention to /code-review skill
Require comments explaining non-trivial technical decisions, with history
of previous approaches. Review step checks for missing reasoning comments,
stale comments, and undocumented approach changes.
* fix: move skill to directory structure for Claude Code discovery
Claude Code requires .claude/skills/<name>/SKILL.md, not loose .md files.
* feat: add branch hygiene checks to /code-review skill
Review step 1 now verifies branch is based on recent origin/main and
all commits are relevant to the feature. Unrelated commits flagged as
must-fix.
