#23183: fix(skill-creator): exclude .git and VCS internals from .skill archives

## Problem `package_skill.py` includes `.git/` internals (and other VCS/build artifacts) in `.skill` archives. This causes: - Unnecessary archive bloat - Git history and metadata leakage in distributable skill packages - Poor artifact hygiene ## Fix Add an exclusion set checked during the `rglob` walk that skips: - `.git`, `.svn`, `.hg` (VCS directories) - `__pycache__` (Python bytecode cache) - `node_modules` (JS dependencies) - `.DS_Store` (macOS metadata) The check uses path parts matching so nested occurrences are also excluded (e.g. `subdir/.git/objects`). ## Changes - `skills/skill-creator/scripts/package_skill.py`: Add `EXCLUDED_DIRS` set and skip matching paths Fixes #23149 <!-- greptile_comment --> <h3>Greptile Summary</h3> Adds VCS and build artifact exclusion to skill packaging to prevent `.git/` internals, `__pycache__`, `node_modules`, and other unwanted files from being included in `.skill` archives. The implementation uses path part matching to filter out any file or directory containing excluded names in its path. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk - The change is a focused security and hygiene improvement with clear logic. The exclusion set covers the most common VCS and build artifacts, and the path-matching approach correctly handles nested directories. The existing security checks (symlink validation) remain intact. - No files require special attention _{Last reviewed commit: 58ebee9} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->