#3933: fix(skills): Make skill scripts executable

The skill creation process has issues executing the script as it tries to execute directly relying on the shebang and it just starts creating the skill "by hand" <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR changes the file mode of the skill-creator helper scripts (`init_skill.py`, `package_skill.py`, `quick_validate.py`) from non-executable to executable, so they can be run directly via their `#!/usr/bin/env python3` shebang (instead of requiring `python …`). This aligns with the skill creation flow described in the PR: the tooling expects to invoke these scripts directly and was failing when the executable bit wasn’t set. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - The change is limited to file permission bits (100644→100755) on three existing Python scripts; no code paths or runtime logic were modified, so the behavioral risk is low and it directly addresses the reported execution issue when relying on shebang invocation. - No files require special attention <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->