feat: add Google Drive knowledge connector

[capacitron]

Fixes #3689

Approach

Follows the same pattern as the SharePoint connector. Uses Google service account JWT auth via the googleapis npm package.

Backend

• Added googledrive to ConnectorTypeSchema, config and checkpoint schemas
• Created googledrive-connector.ts implementing BaseConnector with JWT auth, My Drive + shared drives sync, Google Workspace export, binary file extraction, incremental sync via modifiedTime
• Registered in registry.ts
• Added googleapis dependency

Frontend

• Added label, icon, config fields (sharedDriveIds, folderId)
• Wired into create and edit connector dialogs with service account credentials

[joeyorlando]

hi there 👋 #3689 has already been assigned to another contributor, appreciate the contribution though 🙏