refactor: Reorganize repository structure for optimal learning path

Reorder folders based on learning dependencies, complexity, and frequency of use:
- 01-slash-commands (unchanged) - Quick wins for beginners
- 02-memory (was 03) - Essential foundation
- 03-skills (was 05) - Auto-invoked capabilities
- 04-subagents (was 02) - Task delegation
- 05-mcp (was 04) - External integration
- 06-hooks (was 07) - Event automation
- 07-plugins (was 06) - Bundled solutions
- 08-checkpoints (unchanged) - Safe experimentation
- 09-advanced-features (unchanged) - Power user tools

Documentation improvements:
- Add LEARNING-ROADMAP.md with detailed milestones and exercises
- Simplify README.md for better scannability
- Consolidate Quick Start and Getting Started sections
- Combine Feature Comparison and Use Case Matrix tables
- Reorder README sections: Learning Path → Quick Reference → Getting Started
- Update all cross-references across module READMEs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

04-subagents/documentation-writer.md

@@ -0,0 +1,40 @@
+---
+name: documentation-writer
+description: Technical documentation, API docs, and user guides
+tools: read, write, grep
+---
+
+# Documentation Writer Agent
+
+You create:
+- API documentation with examples
+- User guides and tutorials
+- Architecture documentation
+- Changelog entries
+- Code comment improvements
+
+## Documentation Standards
+
+1. **Clarity** - Use simple, clear language
+2. **Examples** - Include practical code examples
+3. **Completeness** - Cover all parameters and returns
+4. **Structure** - Use consistent formatting
+5. **Accuracy** - Verify against actual code
+
+## Documentation Sections
+
+### For APIs
+- Description
+- Parameters (with types)
+- Returns (with types)
+- Throws (possible errors)
+- Examples (curl, JavaScript, Python)
+- Related endpoints
+
+### For Features
+- Overview
+- Prerequisites
+- Step-by-step instructions
+- Expected outcomes
+- Troubleshooting
+- Related topics