Added topology docs (#584)

Author: romanbaron

docs/topology/README.md

@@ -0,0 +1,43 @@
+# Topology Aware Scheduling
+KAI Scheduler incorporates topology awareness and schedules workloads with consideration for the physical placement of nodes.
+
+## Topological Information
+Topology information is derived from both Kubernetes node labels and the Kueue Topology CRD:
+```yaml
+apiVersion: kueue.x-k8s.io/v1alpha1
+kind: Topology
+metadata:
+  name: "cluster-topology"
+spec:
+  levels:
+  - nodeLabel: "cloud.provider.com/topology-block"
+  - nodeLabel: "cloud.provider.com/topology-rack"
+  - nodeLabel: "kubernetes.io/hostname"
+```
+A topology definition must include at least one level with a label selector. Based on this configuration, KAI Scheduler organizes nodes into hierarchical domains aligned with the specified labels. 
+
+## Topology Constraints
+Workloads that require location-aware scheduling can declare topology constraints via annotations, using either required or preferred placement.
+
+To enforce strict rack-level locality, a workload can be annotated as follows:
+```yaml
+kai.scheduler/topology: "cluster-topology"
+kai.scheduler/topology-required-placement: "cloud.provider.com/topology-rack"
+```
+With a required placement, the scheduler will not place the workload on nodes lacking the specified label.
+
+For soft affinity, the annotation can specify a preferred placement:
+```yaml
+kai.scheduler/topology: "cluster-topology"
+kai.scheduler/topology-preferred-placement: "cloud.provider.com/topology-rack"
+```
+In this case, the scheduler will first target nodes matching the label. If no suitable nodes are available, it will fall back to a higher-level topology domain. 
+
+You can also combine required and preferred placement in a single workload. In this model, the required constraint sets the upper boundary for eligible domains, while the preferred constraint guides the scheduler toward a more granular placement within that boundary. 
+For example, a workload can require block-level placement while preferring rack-level locality, allowing tighter affinity without expanding the scheduling scope to the entire cluster.
+Such constraint can be expressed as:
+```yaml
+kai.scheduler/topology: "cluster-topology"
+kai.scheduler/topology-required-placement: "cloud.provider.com/topology-block"
+kai.scheduler/topology-preferred-placement: "cloud.provider.com/topology-rack"
+```