feat: refactor project structure + add pcguard + AGENT_VERIFY injection

- Restructure: pcexec/ and safe-restart/ → plugin/{tools,core,commands}
- New pcguard Go binary: validates AGENT_VERIFY, AGENT_ID, AGENT_WORKSPACE
- pcexec now injects AGENT_VERIFY env + appends openclaw bin to PATH
- plugin/index.ts: unified TypeScript entry point with resolveOpenclawPath()
- install.mjs: support --openclaw-profile-path, install pcguard, new paths
- README: updated structure docs + security limitations note
- Removed old root index.js and openclaw.plugin.json

plugin/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "padded-cell-plugin",
+  "version": "0.2.0",
+  "description": "PaddedCell plugin for OpenClaw - secure exec, password management, coordinated restart",
+  "main": "index.ts",
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch"
+  },
+  "dependencies": {
+    "@types/node": "^20.0.0",
+    "express": "^4.18.0",
+    "ws": "^8.14.0"
+  },
+  "devDependencies": {
+    "typescript": "^5.0.0",
+    "@types/express": "^4.17.0",
+    "@types/ws": "^8.5.0"
+  }
+}