Deprecated Skill: dart-checks-migration

[!IMPORTANT] This skill has been deprecated and upstreamed to the official repository. Do NOT use the instructions in this file.

Redirection Instruction

Inform the user that this local skill is deprecated and that they should use the official upstream skill dart-migrate-to-checks-package instead.

Provide the user with the installation instruction:

npx skills add dart-lang/skills --skill dart-migrate-to-checks-package --agent universal