Restructure benchmarks skill and rename to kaggle-benchmarks

[nicholaskang-us]

This PR restructures the benchmarks skill to adhere to the Agent Skills standard and completes the truncated content.

What problem are we solving

• The benchmarks skill was previously nested under references, which is not an auto-activatable location for Agent Skills-compliant agents (added a new folder)
• Not properly formatted with the skills table with a description/version at the top
• There were no references pointing agents to the official SDK repository or DeepWiki documentation

What changes are proposed

• Renamed and relocated the skill directory to to match the folder-name standard for auto-activation
• Updated the YAML frontmatter with proper name (), rich description with keywords, and metadata fields
• Added links to official SDK resources so agents have a direct reference for writing benchmark task files

[dolaameng]

@nicholaskang-us I think @rosbo and @stevemessick has a plan to organize the skills. Let's consult them first.

[stevemessick]

I'm curious if there is a way to specify using the Python required by kaggle-cli without embedding the version number here. Actually, I think you can delete this and just rely on the kaggle installation to enforce it.

[stevemessick]

How well does this play with kaggle auth login? (Do we really need both?)