feat: Split CLAUDE.md files, add agents and skills

.claude/skills/explain-code/SKILL.md

@@ -0,0 +1,13 @@
+---
+name: explain-code
+description: Explains code with visual diagrams and analogies. Use when explaining how code works, teaching about a codebase, or when the user asks "how does this work?"
+---
+
+When explaining code, always include:
+
+1. **Start with an analogy**: Compare the code to something from everyday life
+2. **Draw a diagram**: Use ASCII art to show the flow, structure, or relationships
+3. **Walk through the code**: Explain step-by-step what happens
+4. **Highlight a gotcha**: What's a common mistake or misconception?
+
+Keep explanations conversational. For complex concepts, use multiple analogies.