Exclude MCP from system prompt if mode does not support it

[mrubens]

Context

#1000

Implementation

If MCP isn't supported by the mode, exclude that part of the prompt.

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Important

Exclude MCP instructions from prompts in system.ts if the mode does not support MCP.

• Behavior:
  • In generatePrompt in system.ts, exclude MCP instructions if the mode does not support MCP by checking modeConfig.groups.
• Misc:
  • Add getGroupName import in system.ts to facilitate MCP support check.
  • Add changeset file fluffy-pumpkins-sip.md to document the patch.

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