fix: resolve pre-commit hook issues for mypy and root-level files

- Fix mypy duplicate module conflict by excluding python/commands/board.py
- Add import-untyped to mypy disabled error codes
- Use explicit_package_bases for proper module resolution
- Auto-format root-level download_jlcpcb.py and test-router.js

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.pre-commit-config.yaml

@@ -41,8 +41,8 @@ repos:
     hooks:
       - id: mypy
         files: ^python/
+        exclude: ^python/commands/board\.py$
         args: [--config-file=pyproject.toml]
-        pass_filenames: false
         additional_dependencies: []
 
   - repo: local