feat: sync API types, resources and constants with KAI-Scheduler main

[SiorMeir]

Summary

Ports everything that landed in KAI-Scheduler main under the migrated in-tree packages since the api module was last seeded, so KAI-Scheduler#1917 can be rebased onto main and consume it.

• NvFractions GPU sharing: kai/v1/common GpuSharingMode, Global.GpuSharingMode, binder/admission mode-based defaults, and utilities/resources gpu_sharing (container refs, validation, nvfractions, compute mode, memory portion limit); new constants.
• Semi-preemptible: SemiPreemptible preemptibility, PodGroup webhook/type changes, utilities/podgroup IsPreemptible.
• BindRequest: FractionalGpuGroup and SelectedFractionalGpuGroupIDs.
• Admission: configurable serviceName.
• DRA: skip synthetic extended-resource claims.
• Regenerated deepcopy, CRDs and clients.

Validation

• go build ./..., go vet ./..., go test ./... pass.
• All 6 generated CRDs are byte-identical to deployments/kai-scheduler/crds on KAI-Scheduler main.

Notes

utilities/podgroup/preemptible_test.go keeps the local priorityBuildNumber constant so the module does not depend on scheduler internals.

[KaiPilotBot]

📝 Changelog fragment recorded

Thanks! This PR added the changelog fragment(s) below. Pending fragments are folded into CHANGELOG.md at release time, so it was intentionally not modified by this PR — your entry will appear in the next release:

• .changes/unreleased/added-20261004-110555.yaml