docs: add Zenith Hosting deploy option

[odpay]

hey, i work on Zenith Hosting, a startup doing one-click hosting for open source apps. we added Umami to our marketplace, so this PR adds a small "Deploy with Zenith" badge under Getting Started (links to https://zenith.hosting/host/umami).

we share a cut of revenue with the projects we host. happy to explain if you're curious: hello@zenith.hosting

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}

[vercel]

@odpay is attempting to deploy a commit to the Umami Software Team on Vercel.

A member of the Team first needs to authorize it.

[greptile-apps]

Greptile Summary

Adds a Zenith Hosting deployment option to the Getting Started section.

• Adds a linked “Deploy with Zenith” badge.
• Describes the managed hosting features and revenue-sharing arrangement.

Confidence Score: 5/5

The documentation-only change appears safe to merge.

The PR only adds a hosting badge and explanatory text to the README without changing application, build, or deployment behavior.

Important Files Changed

Filename	Overview
README.md	Adds documentation and a deployment badge for Zenith Hosting; no actionable issues identified.

_{Reviews (1): Last reviewed commit: "docs: add Zenith Hosting deploy option" | Re-trigger Greptile}