feat: Split compound-engineering into 5 focused plugins

Addresses #20 - Split project into multiple plugins

New plugin structure:
- compound-engineering-core: 17 agents, 14 commands, 8 skills (framework-agnostic)
- rails-dev: 4 agents, 4 skills (DHH/37signals style)
- python-dev: 1 agent (Python review)
- typescript-dev: 2 agents (TS/JS review)
- frontend-design: 3 agents, 1 skill, Playwright MCP

Original compound-engineering becomes meta-package with docs commands.

Migration guide included in plans/split-into-multiple-plugins.md

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/python-dev/README.md

@@ -0,0 +1,36 @@
+# python-dev
+
+Python development and code review.
+
+## Installation
+
+```bash
+# Requires core plugin
+claude /plugin install compound-engineering-core
+
+# Install Python tools
+claude /plugin install python-dev
+```
+
+## What's Included
+
+### Agents (1)
+
+- `kieran-python-reviewer` - Opinionated Python code review
+
+## Usage
+
+The Python reviewer is automatically used by `/workflows:review` when reviewing Python code:
+
+```bash
+claude /workflows:review 123
+```
+
+## Future Additions
+
+This plugin is small but growing. Planned additions:
+
+- Python style skills
+- FastAPI/Django patterns
+- Type hint reviewer
+- Testing patterns