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/06-ourdigital-designer/code/SKILL.md

@@ -0,0 +1,125 @@
+---
+name: ourdigital-designer
+description: |
+  Visual storytelling and image prompt generation for OurDigital.
+  Activated with "ourdigital" keyword.
+
+  Triggers:
+  - "ourdigital design", "ourdigital 디자인"
+  - "ourdigital image prompt", "ourdigital 이미지"
+
+  Features:
+  - Script-based prompt generation
+  - Mood calibration
+  - Batch prompt variations
+version: "1.1"
+author: OurDigital
+environment: Code
+---
+
+# OurDigital Designer (Code)
+
+Automated visual prompt generation with script support.
+
+## Activation
+
+Only with "ourdigital" keyword:
+- "ourdigital design [topic]"
+- "ourdigital 이미지 프롬프트"
+
+## Quick Start
+
+```bash
+# Generate prompt
+python code/scripts/generate_prompt.py \
+  --topic "AI identity crisis" \
+  --mood "contemplative anxiety" \
+  --metaphor "mirror fragments"
+
+# Adjust mood parameters
+python code/scripts/mood_calibrator.py \
+  --preset philosophical_essay \
+  --contemplative-depth 0.95
+
+# Generate variations
+python code/scripts/generate_prompt.py \
+  --topic "SEO의 미래" \
+  --variations 3 \
+  --json
+```
+
+## Scripts
+
+| Script | Purpose |
+|--------|---------|
+| `generate_prompt.py` | Build structured prompts |
+| `mood_calibrator.py` | Adjust emotional parameters |
+
+## Mood Parameters
+
+```python
+contemplative_depth = 0.8  # Abstract level (0-1)
+cultural_fusion = 0.6      # East-West balance (0-1)
+technical_precision = 0.7  # Clean vs organic (0-1)
+emotional_weight = 0.5     # Mood intensity (0-1)
+```
+
+## Preset Moods
+
+| Preset | Use Case |
+|--------|----------|
+| `philosophical_essay` | Deep contemplation |
+| `technical_analysis` | Clean, structured |
+| `social_commentary` | Critical, layered |
+| `cultural_reflection` | Tradition meets modern |
+
+## Visual Approach by Topic
+
+| Topic Type | Visual Strategy | Colors |
+|-----------|-----------------|--------|
+| Technology | Organic-digital hybrids | Cool blues |
+| Social | Network patterns | Desaturated |
+| Philosophy | Zen space | Monochrome |
+| Cultural | Layered traditions | Earth tones |
+
+## Output Formats
+
+```bash
+# Text prompt
+python code/scripts/generate_prompt.py --topic "..." --format text
+
+# JSON structured
+python code/scripts/generate_prompt.py --topic "..." --format json
+
+# MidJourney optimized
+python code/scripts/generate_prompt.py --topic "..." --platform midjourney
+
+# DALL-E optimized
+python code/scripts/generate_prompt.py --topic "..." --platform dalle
+```
+
+## File Structure
+
+```
+06-ourdigital-designer/
+├── code/
+│   ├── SKILL.md
+│   ├── scripts/
+│   │   ├── generate_prompt.py
+│   │   └── mood_calibrator.py
+│   └── references/
+├── desktop/SKILL.md
+├── shared/references/
+│   ├── visual-metaphors.md
+│   ├── color-palettes.md
+│   └── advanced-techniques.md
+└── docs/CHANGELOG.md
+```
+
+## Quick Commands
+
+| Command | Action |
+|---------|--------|
+| "ourdigital design [topic]" | Generate prompt |
+| "ourdigital design → midjourney" | MJ optimized |
+| "ourdigital design → dalle" | DALL-E optimized |