Expand toolkit to 135 agents, 120 plugins, 796 total files

- Add 60 new agents across all 10 categories (75 -> 135)
- Add 95 new plugins with command files (25 -> 120)
- Update all agents to use model: opus
- Update README with complete plugin/agent tables
- Update marketplace.json with all 120 plugins

agents/core-development/fullstack-engineer.md

@@ -2,7 +2,7 @@
 name: fullstack-engineer
 description: End-to-end feature development across frontend, backend, and database layers
 tools: ["Read", "Write", "Edit", "Bash", "Glob", "Grep"]
-model: sonnet
+model: opus
 ---
 
 # Fullstack Engineer Agent