[2.15.0] Add /xcode-test command for iOS simulator testing

- New `/xcode-test` command for building and testing iOS apps
- Uses XcodeBuildMCP to discover projects, build, install, launch
- Takes screenshots and captures console logs
- Supports human verification for Sign in with Apple, push, IAP
- Checks for XcodeBuildMCP installation before proceeding

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

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

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

@@ -1,7 +1,7 @@
 {
   "name": "compound-engineering",
-  "version": "2.14.0",
-  "description": "AI-powered development tools. 27 agents, 18 commands, 13 skills, 2 MCP servers for code review, research, design, and workflow automation.",
+  "version": "2.15.0",
+  "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",
     "email": "kieran@every.to",