[2.16.0] Expand DHH Rails/Ruby style skills with 37signals patterns

Massively enhanced reference documentation for both dhh-rails-style and
dhh-ruby-style skills by incorporating patterns from Marc Köhlbrugge's
Unofficial 37signals Coding Style Guide.

dhh-rails-style additions:
- controllers.md: Authorization patterns, rate limiting, Sec-Fetch-Site CSRF
- models.md: Validation philosophy, bang methods, Rails 7.1+ patterns
- frontend.md: Turbo morphing, Stimulus controllers, broadcasting patterns
- architecture.md: Multi-tenancy, database patterns, security, Active Storage
- gems.md: Testing philosophy, expanded what-they-avoid section

dhh-ruby-style additions:
- Development philosophy (ship/validate/refine)
- Rails 7.1+ idioms (params.expect, StringInquirer)
- Extraction guidelines (rule of three)

Credit: Marc Köhlbrugge's unofficial-37signals-coding-style-guide

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

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

plugins/compound-engineering/.claude-plugin/plugin.json

@@ -1,6 +1,6 @@
 {
   "name": "compound-engineering",
-  "version": "2.15.2",
+  "version": "2.16.0",
   "description": "AI-powered development tools. 27 agents, 19 commands, 13 skills, 2 MCP servers for code review, research, design, and workflow automation.",
   "author": {
     "name": "Kieran Klaassen",