feat(binder): add NvFractions binding plugin

[davidLif]

Description

Stack PR 3/9 for GPU sharing migration.

Base: codex/nvfractions-scheduler-accounting
Head: codex/nvfractions-binder

This adds the Binder-side NvFractions binding plugin and configuration wiring. It lets Binder translate scheduler allocation data into NvFractions runtime annotations/configuration, updates Binder API config, and adds plugin/unit coverage for the new binding path.

Related Issues

N/A

Checklist

Note: Ensure your PR title follows the Conventional Commits format (e.g., feat(scheduler): add new feature)

• Self-reviewed
• Added/updated tests (if needed)
• Updated documentation (if needed)
• Added a changelog fragment via make changelog (or applied the skip-changelog label). Do not edit CHANGELOG.md directly — pending fragments are folded into it at release time.

Breaking Changes

None.

Additional Notes

Validation run:

go test ./pkg/binder/binding ./pkg/binder/plugins ./pkg/binder/plugins/gpusharing ./pkg/binder/plugins/nvfractions ./pkg/operator/operands/binder ./pkg/apis/kai/v1/binder

[github-actions]

Total coverage: 54.6% -> 54.8% (delta 0.20%)

Merging this branch changes the coverage (3 decrease, 4 increase)

Impacted Packages	Coverage Δ	🤖
github.com/kai-scheduler/KAI-scheduler/pkg/apis/kai/v1/binder	32.73% (+0.41%)	👍
github.com/kai-scheduler/KAI-scheduler/pkg/binder/binding	67.31% (-0.62%)	👎
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins	63.83% (-2.35%)	👎
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/gpusharing	54.76% (+11.43%)	🎉
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/nvfractions	74.36% (+74.36%)	🌟
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/state	0.00% (ø)
github.com/kai-scheduler/KAI-scheduler/pkg/env-tests/utils	0.00% (ø)
github.com/kai-scheduler/KAI-scheduler/pkg/operator/operands/binder	75.58% (+0.89%)	👍
github.com/kai-scheduler/KAI-scheduler/pkg/podgroupcontroller/controllers/resources	81.61% (-1.22%)	👎

---

Coverage by file

Changed files (no unit tests)

Changed File	Coverage Δ	Total	Covered	Missed	🤖
github.com/kai-scheduler/KAI-scheduler/pkg/apis/kai/v1/binder/binder.go	94.74% (+0.09%)	57 (+1)	54 (+1)	3	👍
github.com/kai-scheduler/KAI-scheduler/pkg/binder/binding/binder.go	67.31% (-0.62%)	52 (-1)	35 (-1)	17	👎
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/config.go	98.04% (ø)	51	50	1
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/factory.go	52.78% (-3.94%)	72 (+5)	38	34 (+5)	👎
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/gpusharing/gpu_sharing.go	54.76% (+11.43%)	84 (+24)	46 (+20)	38 (+4)	🎉
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/nvfractions/nv_fractions.go	74.36% (+74.36%)	39 (+39)	29 (+29)	10 (+10)	🌟
github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/state/state.go	0.00% (ø)	0	0	0
github.com/kai-scheduler/KAI-scheduler/pkg/env-tests/utils/utils.go	0.00% (ø)	93	0	93
github.com/kai-scheduler/KAI-scheduler/pkg/operator/operands/binder/resources.go	76.82% (+0.93%)	151 (+10)	116 (+9)	35 (+1)	👍

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.

Changed unit test files

• github.com/kai-scheduler/KAI-scheduler/pkg/apis/kai/v1/binder/binder_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/binder/binding/default_binder_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/binder/binding/fraction_binder_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/gpusharing/gpu_sharing_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/binder/plugins/nvfractions/nv_fractions_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/operator/operands/binder/binder_test.go
• github.com/kai-scheduler/KAI-scheduler/pkg/podgroupcontroller/controllers/resources/fraction_test.go