ci: add CKS nightly dispatch workflow

[zhouyou9505]

Description

Adds a ci-nightly-benchmark-cks.yaml workflow_dispatch entrypoint so the llm-d/llm-d nightly-benchmark-cks workflow can dispatch the CKS benchmark workflow in this repository without hitting:

422: Workflow does not have 'workflow_dispatch' trigger

The new entrypoint preserves the current caller contract, input_dir and output_dir, and fans out to the existing reusable nightly benchmark workflow for the three CKS standup modes:

• Standalone
• ModelService
• FMA

Fixes #1365.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Parsed the new workflow YAML successfully with Python/PyYAML.
• Ran git diff --cached --check before commit.

This is a GitHub Actions dispatch wiring change, so I did not run a full CKS benchmark or cluster standup locally.

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[maugustosilva]

Thanks for the contribution! Fair warning, we are in the process of reworking all workflows on the main llm-d

[zhouyou9505]

Thanks for the contribution! Fair warning, we are in the process of reworking all workflows on the main llm-d

Got it .Thanks for the review.