Update skill-creator and make scripts executable (#350)

- Add `compatibility` optional field to SKILL.md frontmatter spec
- Add validation for `compatibility` field in quick_validate.py
- Rename "hyphen-case" to "kebab-case" terminology in init_skill.py
  and quick_validate.py
- Update max skill name length from 40 to 64 characters
- Make scripts executable (chmod +x) for accept_changes.py,
  comment.py, extract_form_structure.py, add_slide.py, thumbnail.py,
  and recalc.py

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

skills/skill-creator/SKILL.md

@@ -53,7 +53,8 @@ skill-name/
 ├── SKILL.md (required)
 │   ├── YAML frontmatter metadata (required)
 │   │   ├── name: (required)
-│   │   └── description: (required)
+│   │   ├── description: (required)
+│   │   └── compatibility: (optional, rarely needed)
 │   └── Markdown instructions (required)
 └── Bundled Resources (optional)
     ├── scripts/          - Executable code (Python/Bash/etc.)
@@ -65,7 +66,7 @@ skill-name/
 
 Every SKILL.md consists of:
 
-- **Frontmatter** (YAML): Contains `name` and `description` fields. These are the only fields that Claude reads to determine when the skill gets used, thus it is very important to be clear and comprehensive in describing what the skill is, and when it should be used.
+- **Frontmatter** (YAML): Contains `name` and `description` fields (required), plus optional fields like `license`, `metadata`, and `compatibility`. Only `name` and `description` are read by Claude to determine when the skill triggers, so be clear and comprehensive about what the skill is and when it should be used. The `compatibility` field is for noting environment requirements (target product, system packages, etc.) but most skills don't need it.
 - **Body** (Markdown): Instructions and guidance for using the skill. Only loaded AFTER the skill triggers (if at all).
 
 #### Bundled Resources (optional)