Update CLAUDE.md with soul conventions

Sync conventions from soul/conventions/ for LLM-assisted development.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: NewGraphEnvironment

CLAUDE.md

@@ -817,7 +817,8 @@ Skip planning for single-file edits, quick fixes, or tasks with obvious next ste
    - `progress.md` — Session log with timestamps and commit refs
 3. **Commit the plan** — Commit the planning files before starting implementation. This is the baseline.
 4. **Work in atomic commits** — Each commit bundles code changes WITH checkbox updates in the planning files. The diff shows both what was done and the checkbox marking it done.
-5. **Archive when complete** — Move `planning/active/` to `planning/archive/` via `/planning-archive`.
+5. **Code check before commit** — Run `/code-check` on staged diffs before committing. Don't mark a task done until the diff passes review.
+6. **Archive when complete** — Move `planning/active/` to `planning/archive/` via `/planning-archive`.
 
 ## Atomic Commits (Critical)