Summary

• The knowledge-base Drive picker only listed Slides and Docs, so Excel files could not be selected. An .xlsx in Drive is spreadsheetml.sheet, not the native Sheets type, so it needs its own entry.
• Extend the shared KB_DRIVE_MIMES (native Sheets, .xlsx, .xls, .csv). Both the settings manager and the in-chat request-file card use it, so a file picked in one place shows in the other.
• Spreadsheet rows get their own icon and the Sheets viewer URL; the "Docs and Slides" copy is now "Google Drive files".
• Not in this PR: the agent can link these files but has no read path for non-native spreadsheets yet (readDocumentTool only builds a viewer URL).

Test plan

• pnpm run autofix:local , all green except chatHistoryList.test.ts (date-bucket assertion in code this PR does not touch)
• apps/mail/tests/modules/integrations/useGooglePicker.test.ts (new) , list contents, comma-joined setMimeTypes, viewer URL per type; passes alongside requestDriveFileRenderer.test.tsx
• Three fresh-subagent thermo reviews; findings fixed or justified

Verify in prod

No new server behavior or logging: this is a client-side constant change, so there is no Axiom/CloudWatch signal.

• Working: Settings > Connections > Google Drive > add file shows .xlsx/.csv/Sheets alongside Docs and Slides, and a picked .xlsx appears in the linked list with a spreadsheet icon.
• Regression: only Docs and Slides are selectable, or an added Excel file saves but does not appear in the list.

🤖 Generated with Claude Code

Confidence Score: 4/5

The behavior appears safe to merge, but the changed import must satisfy the repository’s explicit absolute-import requirement first.

Findings

1.  Relative import violates guidance ▶

### Issue 1
apps/mail/modules/integrations/google-slides-manager.tsx:12-18
The expanded picker import adds `SPREADSHEET_MIMES` and `driveFileUrl` through `./use-google-picker`, but the repository requires absolute imports. This requirement must be satisfied before merging.

```suggestion
import {
  KB_DRIVE_MIMES,
  MIME_PRESENTATION,
  SPREADSHEET_MIMES,
  driveFileUrl,
  useGooglePicker,
} from '@/modules/integrations/use-google-picker';
```

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Summary

The PR expands the shared knowledge-base Drive picker MIME list to include native Sheets, Excel and CSV files. It also adds spreadsheet icons and viewer URLs, updates the settings copy, and adds picker tests.

_{Reviews (1) · Last reviewed commit: "Merge origin/staging"}