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/references/ghost-api-config.md

@@ -0,0 +1,74 @@
+# Ghost Admin API Configuration
+
+## Configured Channels
+
+| Channel | Domain | API Status |
+|---------|--------|------------|
+| blog.ourdigital.org | Korean main blog | ✅ Configured |
+| journal.ourdigital.org | English journal | ✅ Configured |
+| ourstory.day | Personal essays | ✅ Configured |
+
+## API Endpoints
+
+Base URL pattern: `https://{domain}/ghost/api/admin/`
+
+### Authentication
+Ghost Admin API uses JWT tokens generated from Admin API keys.
+
+```
+Admin API Key Format: {id}:{secret}
+- id: 24 hex characters
+- secret: 64 hex characters
+```
+
+### Key Endpoints
+
+| Endpoint | Method | Purpose |
+|----------|--------|---------|
+| `/posts/` | POST | Create new post |
+| `/posts/{id}/` | PUT | Update existing post |
+| `/images/upload/` | POST | Upload image |
+| `/tags/` | GET/POST | Manage tags |
+
+### Post Creation Payload
+
+```json
+{
+  "posts": [{
+    "title": "Post Title",
+    "html": "<p>Content in HTML</p>",
+    "status": "draft",
+    "tags": [{"name": "tag1"}, {"name": "tag2"}],
+    "feature_image": "https://...",
+    "meta_title": "SEO Title",
+    "meta_description": "SEO Description",
+    "og_title": "Social Title",
+    "og_description": "Social Description",
+    "published_at": "2024-01-15T09:00:00.000Z"
+  }]
+}
+```
+
+### Status Options
+- `draft`: Save without publishing
+- `published`: Publish immediately
+- `scheduled`: Schedule for future (requires `published_at`)
+
+## Future Automation Opportunities
+
+### Zapier Integration Points
+1. **Trigger**: New Notion page in "Working with AI" → Create Ghost draft
+2. **Trigger**: Ghost post published → Share to social channels
+3. **Trigger**: New MD file in iCloud folder → Create Ghost draft
+
+### n8n Workflow Ideas
+1. Research complete → Auto-create drafts across all relevant channels
+2. Scheduled publishing queue management
+3. Cross-posting between Ghost instances
+
+## Security Notes
+
+- API keys stored in environment variables
+- Never expose keys in code or logs
+- Rotate keys if compromised
+- Use separate keys for different integrations