Antigravity sends Google Developer Knowledge MCP requests with empty project resource (projects/) on blank startup

Summary:
Antigravity is sending a request to the Google Developer Knowledge MCP endpoint with an empty project resource name (`projects/`), causing HTTP 400 errors even on a blank startup.

Environment:
- macOS Apple Silicon
- Fresh Antigravity reinstall
- Signed in with Google
- No project/folder open
- No visible MCP servers configured

Observed behavior:
On a brand-new blank prompt, Antigravity returns:

HTTP 400 Bad Request
Invalid project resource name projects/

Example error:
Trajectory ID: 4795836a-fce3-42a1-badb-ca41f4c12d7a
TraceID: 0x2cf040c9c84160d0

Expected behavior:
A blank prompt with no MCP servers configured should not attempt to call Google Developer Knowledge MCP, and should not fail with a project resource error.

What I already tried:
- Removed visible MCP servers
- Restarted Antigravity
- Opened a blank prompt with no folder/project
- Reinstalled the app
- Removed Antigravity local state from Application Support, Preferences, and Caches
- Still reproduced the same error

Notes:
This looks like stale global integration state, cached auth/config, or an app/account-level bug causing Antigravity to call Developer Knowledge MCP with an empty project resource.