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/.claude-plugin/plugin.json

@@ -0,0 +1,17 @@
+{
+  "name": "python-dev",
+  "version": "1.0.0",
+  "description": "Python development and review. 1 agent for opinionated Python code review.",
+  "author": {
+    "name": "Kieran Klaassen",
+    "email": "kieran@every.to",
+    "url": "https://github.com/kieranklaassen"
+  },
+  "homepage": "https://github.com/EveryInc/compound-engineering-plugin",
+  "repository": "https://github.com/EveryInc/compound-engineering-plugin",
+  "license": "MIT",
+  "keywords": [
+    "python",
+    "code-review"
+  ]
+}