Convert /data prompt to custom agent (#280651)

* Initial plan

* Create data custom agent from existing prompt

Co-authored-by: TylerLeonhardt <[email protected]>

* Remove original data.prompt.md (converted to agent)

Co-authored-by: TylerLeonhardt <[email protected]>

* update tools again

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: TylerLeonhardt <[email protected]>
Co-authored-by: Tyler Leonhardt <[email protected]>