Update test mode for Vitest

[mrubens]

Important

Update test mode from Jest to Vitest in .roomodes, including role definitions, file regex, and custom instructions.

• Behavior:
  • Update test mode from Jest to Vitest in .roomodes.
  • Change role definition to focus on Vitest expertise.
  • Update file regex to include .spec files and Vitest config files.
• Instructions:
  • Modify custom instructions to reflect Vitest usage, including test running requirements and function imports.
• Misc:
  • Update whenToUse description for test mode.

^{This description was created by for 1151625. You can customize this summary. It will automatically update as commits are pushed.}

[daniel-lxs]

Looks good! I like that Sonnet 4 was encouraged to take a look at other tests before creating one.