OLS-3018 Add kill switch spec for AgenticOLSConfig CR

[thoraxe]

Summary

• Adds .ai/spec/what/system-config.md specifying the new AgenticOLSConfig cluster-scoped singleton with spec.suspended kill switch
• Introduces EmergencyStopped terminal phase for proposals terminated by the kill switch
• Specifies console banner and CLI oc agentic suspend/resume commands
• Updates existing specs (crd-api, proposal-lifecycle, sandbox-execution, reconciler) to integrate the new condition type and phase

Details

This is a spec-only change — no code changes. The spec defines behavioral rules for:

• AgenticOLSConfig CRD (cluster-scoped singleton, spec.suspended bool)
• Emergency termination of in-flight proposals (sandbox pod cleanup, RBAC cleanup, EmergencyStopped condition)
• Reconciler integration via early-return guard and AgenticOLSConfig watch
• Console danger banner when system is suspended
• CLI status reporting and suspend/resume commands

Test plan

• Review spec consistency across all modified files
• Verify EmergencyStopped is correctly added to DerivePhase precedence in proposal-lifecycle.md
• Verify cross-references between system-config.md and other specs are correct

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[openshift-ci]

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