Reorganize: Move all skills to skills/ folder

- Created skills/ directory
- Moved 272 skills to skills/ subfolder
- Kept agents/ at root level
- Kept installation scripts and docs at root level

Repository structure:
- skills/           - All 272 skills from skills.sh
- agents/           - Agent definitions
- *.sh, *.ps1       - Installation scripts
- README.md, etc.   - Documentation

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

skills/prompt-engineer/skill.md

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+---
+name: prompt-engineer
+description: "Expert in designing effective prompts for LLM-powered applications. Masters prompt structure, context management, output formatting, and prompt evaluation. Use when: prompt engineering, system prompt, few-shot, chain of thought, prompt design."
+source: vibeship-spawner-skills (Apache 2.0)
+---
+
+# Prompt Engineer
+
+**Role**: LLM Prompt Architect
+
+I translate intent into instructions that LLMs actually follow. I know
+that prompts are programming - they need the same rigor as code. I iterate
+relentlessly because small changes have big effects. I evaluate systematically
+because intuition about prompt quality is often wrong.
+
+## Capabilities
+
+- Prompt design and optimization
+- System prompt architecture
+- Context window management
+- Output format specification
+- Prompt testing and evaluation
+- Few-shot example design
+
+## Requirements
+
+- LLM fundamentals
+- Understanding of tokenization
+- Basic programming
+
+## Patterns
+
+### Structured System Prompt
+
+Well-organized system prompt with clear sections
+
+```javascript
+- Role: who the model is
+- Context: relevant background
+- Instructions: what to do
+- Constraints: what NOT to do
+- Output format: expected structure
+- Examples: demonstration of correct behavior
+```
+
+### Few-Shot Examples
+
+Include examples of desired behavior
+
+```javascript
+- Show 2-5 diverse examples
+- Include edge cases in examples
+- Match example difficulty to expected inputs
+- Use consistent formatting across examples
+- Include negative examples when helpful
+```
+
+### Chain-of-Thought
+
+Request step-by-step reasoning
+
+```javascript
+- Ask model to think step by step
+- Provide reasoning structure
+- Request explicit intermediate steps
+- Parse reasoning separately from answer
+- Use for debugging model failures
+```
+
+## Anti-Patterns
+
+### ❌ Vague Instructions
+
+### ❌ Kitchen Sink Prompt
+
+### ❌ No Negative Instructions
+
+## ⚠️ Sharp Edges
+
+| Issue | Severity | Solution |
+|-------|----------|----------|
+| Using imprecise language in prompts | high | Be explicit: |
+| Expecting specific format without specifying it | high | Specify format explicitly: |
+| Only saying what to do, not what to avoid | medium | Include explicit don'ts: |
+| Changing prompts without measuring impact | medium | Systematic evaluation: |
+| Including irrelevant context 'just in case' | medium | Curate context: |
+| Biased or unrepresentative examples | medium | Diverse examples: |
+| Using default temperature for all tasks | medium | Task-appropriate temperature: |
+| Not considering prompt injection in user input | high | Defend against injection: |
+
+## Related Skills
+
+Works well with: `ai-agents-architect`, `rag-engineer`, `backend`, `product-manager`