feat: complete OpenCode plugin support with hooks, tools, and commands

Major OpenCode integration overhaul:

- llms.txt: Comprehensive OpenCode documentation for LLMs (642 lines)
- .opencode/plugins/ecc-hooks.ts: All Claude Code hooks translated to OpenCode's plugin system
- .opencode/tools/*.ts: 3 custom tools (run-tests, check-coverage, security-audit)
- .opencode/commands/*.md: All 24 commands in OpenCode format
- .opencode/package.json: npm package structure for opencode-ecc
- .opencode/index.ts: Main plugin entry point

- Delete incorrect LIMITATIONS.md (hooks ARE supported via plugins)
- Rewrite MIGRATION.md with correct hook event mapping
- Update README.md OpenCode section to show full feature parity

OpenCode has 20+ events vs Claude Code's 3 phases:
- PreToolUse → tool.execute.before
- PostToolUse → tool.execute.after
- Stop → session.idle
- SessionStart → session.created
- SessionEnd → session.deleted
- Plus: file.edited, file.watcher.updated, permission.asked, todo.updated

- 12 agents: Full parity
- 24 commands: Full parity (+1 from original 23)
- 16 skills: Full parity
- Hooks: OpenCode has MORE (20+ events vs 3 phases)
- Custom Tools: 3 native OpenCode tools

The OpenCode configuration can now be:
1. Used directly: cd everything-claude-code && opencode
2. Installed via npm: npm install opencode-ecc

.opencode/package.json

@@ -0,0 +1,70 @@
+{
+  "name": "opencode-ecc",
+  "version": "1.0.0",
+  "description": "Everything Claude Code (ECC) plugin for OpenCode - agents, commands, hooks, and skills",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./plugins": {
+      "types": "./dist/plugins/index.d.ts",
+      "import": "./dist/plugins/index.js"
+    },
+    "./tools": {
+      "types": "./dist/tools/index.d.ts",
+      "import": "./dist/tools/index.js"
+    }
+  },
+  "files": [
+    "dist",
+    "commands",
+    "prompts",
+    "instructions",
+    "opencode.json",
+    "README.md"
+  ],
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist",
+    "prepublishOnly": "npm run build"
+  },
+  "keywords": [
+    "opencode",
+    "plugin",
+    "claude-code",
+    "agents",
+    "ecc",
+    "ai-coding",
+    "developer-tools",
+    "hooks",
+    "automation"
+  ],
+  "author": "affaan-m",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/affaan-m/everything-claude-code.git"
+  },
+  "bugs": {
+    "url": "https://github.com/affaan-m/everything-claude-code/issues"
+  },
+  "homepage": "https://github.com/affaan-m/everything-claude-code#readme",
+  "publishConfig": {
+    "access": "public"
+  },
+  "peerDependencies": {
+    "@opencode-ai/plugin": ">=1.0.0"
+  },
+  "devDependencies": {
+    "@opencode-ai/plugin": "^1.0.0",
+    "@types/node": "^20.0.0",
+    "typescript": "^5.3.0"
+  },
+  "engines": {
+    "node": ">=18.0.0"
+  }
+}