Validate-skill-structure.py reports false errors for audit-trail Korean section headings

## Summary

`scripts/validate-skill-structure.py` reports 2 errors for `plugins/agenticops/skills/audit-trail/SKILL.md` because it checks for English-only section headings, but `audit-trail` uses Korean headings.

## Reproduction

```bash
python3 scripts/validate-skill-structure.py
```

Output:

```
[1/4] Section Structure Validation
--------------------------------------------------
❌ audit-trail
Missing required section: '## When to Use'
Missing required section: '## Prerequisites'
```

## Root Cause

`validate-skill-structure.py` defines required sections as:

```python
REQUIRED_SECTIONS = [
"When to Use",
"Prerequisites",
"참고 자료",
]
```

But `audit-trail/SKILL.md` uses Korean equivalents:

| Expected (English) | Actual (Korean) |
|---|---|
| `## When to Use` | `## 언제 사용하나요` |
| `## Prerequisites` | `## 전제 조건` |
| `## 참고 자료` | `## 참고 자료` ✅ |

All other 10 agenticops skills use English section headings and pass validation.

## Possible Fixes

**Option A** — Update `validate-skill-structure.py` to accept both English and Korean section names:

```python
REQUIRED_SECTIONS = [
("When to Use", "언제 사용하나요"),
("Prerequisites", "전제 조건"),
("참고 자료",),
]
```

**Option B** — Rename `audit-trail`'s section headings to English to match the other 10 skills.

## Impact
- No functional impact — this is a documentation structure check only.

Start with scripts/validate-skill-structure.py and inspect the section checks against plugins/agenticops/skills/audit-trail/SKILL.md. Run `python3 scripts/validate-skill-structure.py` before and after the change, using one of the two documented approaches. Done means the audit-trail skill no longer reports false missing-section errors while the other skills continue to validate.

Written by the indexing model from the issue text.