feat: add Google Drive knowledge connector

[CalvinMagezi]

Summary

Closes #3689 — adds a Google Drive knowledge connector for syncing documents and files into the Archestra knowledge base.

• Backend connector (google-drive-connector.ts): Uses the Drive REST API v3 directly (no SDK dependency). Supports dual auth: paste a service account JSON key (auto-generates JWT via node:crypto) or a raw OAuth 2.0 access token.
• Incremental sync: Uses modifiedTime with a 5-minute safety buffer to avoid re-syncing unchanged files.
• Supported formats: Google Docs (exported as plain text), Sheets (CSV), Slides (plain text), .txt, .md, .csv, .json, .html.
• Filtering: Shared Drive (driveId), folder (folderId), MIME type (mimeTypes).
• Test suite: 11 vitest tests covering config validation, connection testing, sync batching, pagination, checkpoint advancement, folder/drive filtering, and query building.
• Frontend: Google Drive option in create/edit dialogs with config fields for Shared Drive ID, folder ID, and MIME type filter.

Files changed

File	Change
platform/backend/src/knowledge-base/connectors/google-drive/google-drive-connector.ts	New — core connector implementation
platform/backend/src/knowledge-base/connectors/google-drive/google-drive-connector.test.ts	New — vitest test suite
platform/backend/src/knowledge-base/connectors/registry.ts	Register GoogleDriveConnector
platform/backend/src/types/knowledge-connector.ts	Add GoogleDriveConfigSchema, GoogleDriveCheckpointSchema, googledrive type
platform/shared/knowledge-base.ts	Add googledrive: "Google Drive" label
platform/frontend/public/icons/google-drive.png	Google Drive icon
platform/frontend/src/app/knowledge/knowledge-bases/_parts/connector-icons.tsx	Register icon
platform/frontend/src/app/knowledge/knowledge-bases/_parts/google-drive-config-fields.tsx	New — config fields component
platform/frontend/src/app/knowledge/knowledge-bases/_parts/create-connector-dialog.tsx	Add Google Drive option
platform/frontend/src/app/knowledge/knowledge-bases/_parts/edit-connector-dialog.tsx	Add Google Drive config fields
platform/frontend/src/app/knowledge/knowledge-bases/_parts/transform-config-array-fields.ts	Add mimeTypes to array fields

Test plan

• Create a Google Drive connector using a service account JSON key
• Create a Google Drive connector using a raw OAuth access token
• Run earn_discover to verify the connector appears in the list
• Trigger a sync and verify Google Docs are ingested as plain text
• Trigger a sync with folderId set and verify only files from that folder are synced
• Verify the lastSyncedAt checkpoint advances after each sync
• Run pnpm test in platform/backend to verify all unit tests pass

🤖 Generated with Claude Code

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[joeyorlando]

hi there 👋 #3689 has already been assigned to another contributor, but thank you for your contribution 🙏