Refactor CLI config to use server-backed updates

[owenqwenstarsky]

Summary

• split CLI connection state from server runtime config by adding ~/.buddy/cli/config.json and ~/.buddy/cli/key.txt
• route config panel reads and writes through new socket protocol messages instead of editing the server config file directly
• update socket client/server auth and startup flow so the CLI connects to a configured server and only auto-starts the local server when appropriate
• rename path helpers to distinguish CLI-owned files from server-owned files and improve config panel messaging

Testing

• npm run check
• npm test