feat: add ZPan app

[saltbo]

Summary

• Add ZPan as a 1Panel app store package.
• Use the official GHCR images ghcr.io/saltbo/zpan:2.7.1 and ghcr.io/saltbo/zpan:2.7.1-cli.
• Deploy both the ZPan web service and downloader node, including downloader BitTorrent port configuration.
• Include app metadata, multilingual README files, install form fields, compose template, and updated logo.

Validation

• Parsed app metadata with yq.
• Rendered docker compose config with 1Panel environment variables.
• Started the compose template locally and verified GET /api/health returned { "status": "ok" }.
• Confirmed the downloader container starts, points to http://zpan:8222, and prints the device authorization URL.

Note: the template pins 2.7.1 instead of latest because the current latest tag resolves to the downloader image config, while 2.7.1 resolves to the web service image.