chore: Update cspell.config.yml to add pyproject

```bash
Run echo "${PR_TITLE}" | npx cspell-cli lint stdin
npm warn exec The following package was not found and will be installed: [email protected]
1/1  624.76ms X
:1:13 - Unknown word (pyproject)
CSpell: Files checked: 1, Issues found: 1 in 1 file.
Error: Process completed with exit code 1.
```

See https://github.com/cpp-linter/cpp-linter-hooks/actions/runs/18933796424/job/54055765818?pr=137

Author: shenxianpeng

cspell.config.yml

@@ -9,6 +9,7 @@ words:
   - htmlcov
   - mkdocs
   - peaceiris
+  - pyproject
   - pipx
   - pypi
   - rustup