chore(backend): add TLS certificate rotation documentation and helper scripts. Fixes #12328

[rahul810050]

chore(backend): add TLS certificate rotation documentation and helper scripts. Fixes #12328

Description of your changes:

This PR adds missing documentation for TLS certificate rotation required when using the pod-to-pod TLS feature introduced in PR #12082. When TLS secrets are renewed, backend services (API server, persistence agent, metadata writer, cache server, etc.) do not automatically reload updated certificate data. A rolling restart is required. This behavior was previously undocumented.

The updates included in this PR:

1. Documentation update (backend/README.md):

   • Added a new section “TLS Certificate Rotation (Pod-to-Pod TLS)”.
   • Explained why certificate rotation is needed, how secrets interact with backend components, and why pods must be restarted.
   • Added a complete, copy-paste-ready rotation procedure:
     • Generate/obtain new TLS certs (server.crt / server.key)
     • Update the TLS secret using kubectl create secret tls ... | kubectl apply -f -
     • Restart affected deployments with kubectl rollout restart
     • Verify rollouts and confirm certificate is active.
   • Added best practices, troubleshooting notes, common errors, and automation guidance (cert-manager + checksum annotations).
   • Added cluster discovery commands to help users identify the exact secret and deployments referencing it.

2. Helper scripts added (optional but helpful for operators):

   • scripts/find-tls-refs.sh
     Identifies which pods/deployments reference the TLS secret (via volumes or env secretKeyRef).
     Helps operators know exactly which deployments must be restarted.
   • scripts/rotate-tls.sh
     Applies new TLS cert/key to the Kubernetes Secret and automatically restarts all deployments referencing the secret, waiting for rollout completion.

3. General improvements:

   • Normalized README formatting.
   • Ensured all examples are reproducible and use correct fenced code blocks.
   • Provided safer and clearer operational guidance for cluster administrators.

These changes directly address the missing operational documentation noted in issue #12328 and align with the maintainers’ suggestion to include example commands.

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Links

• Related feature PR (TLS implementation): feat(backend/frontend): Implement TLS for apiserver HTTP/GRPC #12082
• Documentation issue: chore(backend): Add documentation for TLS cert rotation #12328

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[google-oss-prow]

Hi @rahul810050. Thanks for your PR.

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