Changes:
1. Add /ego-mgr slash command with subcommands:
- get, set, list, delete, add-column, add-public-column, show
- Uses pcExec to call ego-mgr binary with proper env vars
2. Rename pcexec → pc-exec throughout codebase:
- Tool name: pcexec → pc-exec
- Function exports: pcexec → pcExec, pcexecSync → pcExecSync
- Updated all references in skills and plugin files
3. Translate all Chinese text to English:
- ego-mgr-slash.ts responses
- slash-commands.ts responses
- SKILL.md files remain in English
- 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
