Add Gmail, Google Drive, and Google Calendar plugins

[n2parko]

Summary

• Add three discrete Google Workspace plugins named gmail, google-drive, and google-calendar.
• Keep each plugin focused on a specific operational use case with one skill, one custom agent, and one scoped MCP config.
• Wire all three plugins into .cursor-plugin/marketplace.json and root README.md plugin table.

Testing

• npm install --no-save ajv ajv-formats && node scripts/validate-plugins.mjs
  • Result: All plugins validated successfully.

Notes

• Names and installation commands are now:
  • /add-plugin gmail
  • /add-plugin google-drive
  • /add-plugin google-calendar
• MCP server entries were renamed consistently to match plugin IDs.

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