docs(claude): note to close issues with Closes #N

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Toilal

CLAUDE.md

@@ -89,3 +89,4 @@ The library is built around a pipeline: **Patterns -> Matches -> Rules**.
 - Doctests run as part of the default `pytest` invocation: module docstrings (`--doctest-modules`) and the `README.md` examples (`--doctest-glob`). Keep examples version-stable across the supported Python range (e.g. avoid relying on `OrderedDict` repr, which changed in 3.12).
 - Linting/formatting is **ruff** with an extended rule set (`E,W,F,I,UP,B,C4,SIM,PIE,RET,ISC,TC,FA,PT,RUF`). A `.pre-commit-config.yaml` runs ruff + mypy + commitizen as `local`/`system` hooks via `uv run`, so they use the exact versions pinned in the `dev` group / `uv.lock`.
 - **The entire codebase (library + tests) is fully typed and `mypy` runs in strict mode** (`uv run mypy`). The package ships a `py.typed` marker (PEP 561), so keep new code annotated and strict-clean.
+- **Close issues from the PR/commit that resolves them** with a `Closes #N` line (one per issue) in the PR body or commit message, so GitHub auto-closes them on merge to the default branch.