[codex] revert k8s proxy docs updates

[officialasishkumar]

What has changed?

Reverts the k8s-proxy documentation content requested for rollback:

• Reverts 9ef5086964be104336b3e416a7b5d5eb5b627a30 / docs(k8s-proxy): add DaemonSet architecture + auto-replay environments guide #842: docs(k8s-proxy): add DaemonSet architecture + auto-replay environments guide
• Reverts c352a429304e0d7cae96dd71f72634c1084d7dce / docs(k8s-proxy): add Kubernetes Proxy REST API and DaemonSet recording mode #838: docs(k8s-proxy): add Kubernetes Proxy REST API and DaemonSet recording mode

This removes the added docs, sidebar entries, quickstart DaemonSet-mode additions, and Vale vocabulary entries from those two commits while preserving later commits on main.

Note: the current Google.Units = NO Vale override is left unchanged because the active PR Vale workflow fails on pre-existing k8s/K8s text without it.

This PR does not resolve a tracked issue; it reverts #838 and #842.

Type of change

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).
• Documentation update (if none of the other choices apply).

How Has This Been Tested?

• git diff --check origin/main...HEAD
• npx prettier --check versioned_docs/version-3.0.0/quickstart/k8s-proxy.md versioned_docs/version-4.0.0/quickstart/k8s-proxy.md
• npx -y -p node@20 -c 'node --version && npm run build'

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.