doc: add Kubernetes deployment guide with Helm chart

[mberlofa]

Summary

Adds a Kubernetes platform deployment page to the self-hosting documentation, using the community-maintained HelmForge Helm chart.

Related to appwrite/appwrite#11743

Changes

• New page: src/routes/docs/advanced/self-hosting/platforms/kubernetes/+page.markdoc
  • Installation via Helm repository and OCI registry
  • Configuration examples (ingress, SMTP)
  • Architecture overview (API, Console, Realtime, workers, schedulers)
  • External database configuration (MariaDB, Redis)
• Navigation: Added "Kubernetes" entry to the Platform deployment sidebar

Notes

• The chart uses the official appwrite/appwrite image — no custom or repackaged containers
• Includes a callout noting this is a community resource maintained by HelmForge
• Follows the same markdoc structure and section patterns as existing platform pages (AWS, Coolify, etc.)

[greptile-apps]

Greptile Summary

This PR adds a Kubernetes deployment guide for Appwrite self-hosting via the community-maintained HelmForge Helm chart, along with a sidebar navigation entry. The documentation is well-structured and follows the same markdoc conventions as the existing platform pages (AWS, Coolify, etc.).

Key changes:

• New +page.markdoc covering prerequisites, Helm installation (repo and OCI paths), deployment verification, configuration, architecture overview, and external database setup.
• Sidebar navigation entry for the new page added in +layout.svelte.
• All issues raised in the prior review round have been addressed: the OCI install is now correctly presented as an in-place alternative to Step 2 (no longer conflicting with the Helm repo path); the port-forward command uses svc/appwrite-appwrite-console; a secrets management callout is included; and the "Configure services" link now points to the valid /docs/advanced/self-hosting/configuration/environment-variables page.
• One minor remaining gap: the helm upgrade --install command in the Configuration section only shows the Helm repo variant, leaving OCI users without a matching upgrade example.

Confidence Score: 5/5

Safe to merge — all prior P1 concerns have been addressed and the only remaining finding is a minor P2 documentation completeness suggestion.

All blocking issues from the previous review (OCI install conflict, wrong service name in port-forward, missing secrets guidance, broken config link) are resolved. The one remaining comment is a P2 style suggestion about adding an OCI alternative to the upgrade command, which does not block correctness or user safety.

No files require special attention.

Important Files Changed

Filename	Overview
src/routes/docs/advanced/self-hosting/+layout.svelte	Adds a 'Kubernetes' sidebar navigation entry pointing to the new platform page — straightforward, correct placement after Coolify.
src/routes/docs/advanced/self-hosting/platforms/kubernetes/+page.markdoc	New Kubernetes deployment guide using the HelmForge community Helm chart. All issues from the previous review round (OCI path conflict, port-forward service name, secrets callout, broken config link) have been resolved. Minor: the upgrade command in the Configuration section only shows the Helm repo path with no OCI alternative for users who installed via OCI.

_{Reviews (3): Last reviewed commit: "doc: use upgrade --install and fix confi..." | Re-trigger Greptile}