Docs: self-managed KAS examples use grpcs:// by default

Vishal Takrequested to merge
vtak/docs-kas-grpcs-self-managed into master

What does this MR do?

Updates the self-managed GitLab Relay (KAS) defaults and examples from wss://gitlab.example.com/-/kubernetes-agent/ to grpcs://gitlab.example.com, and describes when WebSocket is still used: no HTTPS, a relative URL root, bundled NGINX or HTTP/2 disabled, or TLS terminated at a load balancer. Also adds a GitLab 19.5 upgrade note.

Related issues

Related to #628216 (closed)

Author's checklist

  • Follows the documentation process, guidelines, and style guide.
  • Technical Writer review requested.
Edited by Vishal Tak

Merge request reports