Topology-aware workload scheduling

This KEP describes the architectural design and implementation details for integrating a Topology-Aware workload scheduling algorithm into the Kubernetes kube-scheduler to address the complex placement requirements of modern, high-performance distributed applications. The proposed topology algorithm leverages the workload-oriented scheduling lifecycle introduced in KEP-4671, rather than fundamentally altering the scheduling loop itself. It extends this foundation by enabling the evaluation of scheduling options within specific "Placements" (subsets of the cluster). These Placements represent candidate domains (sets of nodes) where the entire workload is theoretically feasible. The scheduler then simulates the placement of the full group of pods within these domains, utilizing existing filtering and scoring logic to ensure high-fidelity decisions before committing resources. This design introduces specific extensions to the Kubernetes Workload API to support TopologyConstraints, defines new interfaces within the Scheduling Framework (PlacementGeneratePlugin, PlacementScorePlugin), and details the algorithmic flow required to schedule Pod Groups while maintaining compatibility with the scheduler's existing ecosystem.