Remove chat credential rotation requirement

[asarkar157]

Summary

• remove the repository policy that requires rotating credentials solely because they were pasted into chat
• retain existing boundaries against committing or printing secrets
• update the OpsVerse and Grafana documentation to match

Validation

• tofu -chdir=infra/aws fmt -check -recursive
• tofu -chdir=infra/aws validate
• verified no remaining repository requirement ties rotation to credentials pasted into chat

[asarkar157]

Security review — Allowed

Scope: Security gate run #31815190072 for commit 8efcbce39b8d4bdd29024243b231bd9f9bdd68e0.

• Blocking findings: None.
• Advisory findings: None.
• Evidence: Gitleaks, Semgrep, Trivy, tests, policies, and aggregate security-gate completed successfully. Scanner artifacts contained no findings; required evidence was present.

Next action: No security remediation is required by this gate.