Add Codex CLI plugin manifest

[internet-dot]

This adds a small metadata pass so the repo is easier to wire into Codex without touching runtime code.

I targeted this repo because it already exposes:

• Online statistics for server indicators such as CPU usage, memory usage, load average, and disk usage
• Cluster management supporting mirroring operations to multiple nodes, making multi-server environments easy to manage

It adds .codex-plugin/plugin.json, a starter .mcp.json, and the scanner workflow.
Permissions: read-only. No secrets. No publish. No runtime changes.
If you want different command wiring or metadata values, I can adjust the branch.

[0xJacky]

Thanks for the PR. I do not think this is ready to merge yet.

Findings:

1. The new scanner workflow does not run for this repository's active PR flow. The workflow only listens to pushes and pull requests targeting main, but this PR targets dev, and the repository's default remote HEAD is dev. Existing workflows in this checkout also target dev. As a result, this PR currently reports no checks, so the new quality gate is not validating the manifest it introduces.

2. The MCP server command in .mcp.json is not usable as written. It configures npx 0xJacky-nginx-ui, but that package is not available on npm, and npm also rejects that package name because it contains uppercase characters. This means the plugin metadata points Codex at a command that cannot resolve. If this is intended to execute an external package later, the package name, ownership, and publishing path should be made explicit before merging.

Please update the workflow trigger to cover dev and replace the MCP command with a real, owned, installable server command, or remove the MCP server entry until it exists.