feat: Add OurDigital custom skills package (10 skills)

Complete implementation of OurDigital skills with dual-platform support
(Claude Desktop + Claude Code) following standardized structure.

Skills created:
- 01-ourdigital-brand-guide: Brand reference & style guidelines
- 02-ourdigital-blog: Korean blog drafts (blog.ourdigital.org)
- 03-ourdigital-journal: English essays (journal.ourdigital.org)
- 04-ourdigital-research: Research prompts & workflows
- 05-ourdigital-document: Notion-to-presentation pipeline
- 06-ourdigital-designer: Visual/image prompt generation
- 07-ourdigital-ad-manager: Ad copywriting & keyword research
- 08-ourdigital-trainer: Training materials & workshop planning
- 09-ourdigital-backoffice: Quotes, proposals, cost analysis
- 10-ourdigital-skill-creator: Meta skill for creating new skills

Features:
- YAML frontmatter with "ourdigital" or "our" prefix triggers
- Standardized directory structure (code/, desktop/, shared/, docs/)
- Shared environment setup (_ourdigital-shared/)
- Comprehensive reference documentation
- Cross-skill integration support

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

custom-skills/04-ourdigital-research/code/assets/blog-template.md

@@ -0,0 +1,87 @@
+# {제목 / Title}
+
+> **요약**: {1-2문장 핵심 요약}
+> 
+> **Summary**: {1-2 sentence key takeaway}
+
+---
+
+## 들어가며 / Introduction
+
+{독자의 관심을 끄는 도입부. 문제 제기, 질문, 또는 흥미로운 사실로 시작.}
+
+{Opening hook that captures reader attention. Start with a problem, question, or interesting fact.}
+
+---
+
+## 배경 / Background
+
+{주제에 대한 맥락 설명. 왜 이것이 중요한지, 현재 상황은 어떤지.}
+
+{Context for the topic. Why this matters, current state of things.}
+
+---
+
+## 핵심 내용 / Key Points
+
+### 첫 번째 포인트 / First Point
+
+{상세 설명과 근거}
+
+{Detailed explanation with evidence}
+
+### 두 번째 포인트 / Second Point
+
+{상세 설명과 근거}
+
+{Detailed explanation with evidence}
+
+### 세 번째 포인트 / Third Point
+
+{상세 설명과 근거}
+
+{Detailed explanation with evidence}
+
+---
+
+## 실무 적용 / Practical Application
+
+{독자가 바로 적용할 수 있는 액션 아이템}
+
+{Actionable items readers can implement immediately}
+
+1. **첫 번째 단계**: {설명}
+2. **두 번째 단계**: {설명}
+3. **세 번째 단계**: {설명}
+
+---
+
+## 마치며 / Conclusion
+
+{핵심 메시지 재강조, 독자에게 남기는 생각거리 또는 다음 단계}
+
+{Reinforce key message, leave reader with thought or next step}
+
+---
+
+## 참고 자료 / References
+
+- [출처 1](URL)
+- [출처 2](URL)
+- [출처 3](URL)
+
+---
+
+**태그 / Tags**: #{tag1} #{tag2} #{tag3}
+
+**카테고리 / Category**: {category}
+
+---
+
+<!-- 
+SEO Meta (Ghost/CMS용):
+- Meta Title: {60자 이내}
+- Meta Description: {150-160자}
+- URL Slug: {짧고-명확한-슬러그}
+- Featured Image Alt: {이미지 설명}
+-->