docs(services): add Marimo Hub

[peter-gy]

Summary

• document the Marimo Hub one-click service architecture and first login
• cover access policy, compute profiles, managed AI, integrations, GitHub source control, notifications, backups, and security
• add a browser-validated notebook screenshot and regenerate the service directory

Companion service discussion: coollabsio/coolify#11504
Companion core template PR: coollabsio/coolify#11508

Validation

• bun run types:check
• bun run build
• browser render and console check for /docs/services/marimo-hub
• every external documentation link added by this page returns HTTP 200

The repository-wide link checker continues to report its existing localhost links and redirect targets.

AI assistance

Codex helped research the upstream configuration contract, draft the page, and validate the rendered result. The content was checked against the Marimo Hub source and a fresh live Coolify deployment.

[github-actions]

Hi @peter-gy,

This PR was automatically closed because it has no description.

You can either fix this PR or open a new one. If you'd like this PR to be reopened, feel free to ping "ShadowArcanist" (preferred) or another maintainer.

[peter-gy]

@ShadowArcanist The full PR description has been restored, both companion links are present, and validate-pr is green. The description was briefly blank while I corrected the cross-links, which triggered the automatic close. GitHub rejects author-side reopen attempts for this PR. Could you please reopen #679? The branch and four-file diff remain intact.

[ShadowArcanist]

I can't re-open because it says:

[peter-gy]

Ahh, I see, thanks for looking into this @ShadowArcanist. Just opened #680 as a replacement.