[BUG] Composio toolkit connect: 400 error

### Problem statement

Attempting to connect Composio toolkits results in 400 error, but successfully creates the requested auth config on the Composio side. Toolkits are unable to be connected.

### What I did

1. Open settings
2. Navigate to Tools Library
3. Sign up for Composio
4. Enter API key
5. Browse Composio toolkits in Rowboat tools library
6. Select any toolkit and press "Connect"

### What I expected

Composio connection that could be used by Rowboat agents

### What actually happened

- 400 error toast notification
- Successfully created auth config in Composio UI

### What I tried in order to recover

- Restarting Rowboat
- Removing Composio auth configs in Composio UI
- Connecting Composio auth configs to my accounts in Composio UI
- Creating my own auth configs in Composio UI

Reproduce the issue through Settings → Tools Library → a Composio toolkit → Connect, using the API-key setup described in the report. Trace the toolkit connection flow and the 400 response, especially the case where Composio creates the auth config successfully. Done means a toolkit connects successfully and can be used by Rowboat agents without the 400 toast.

Written by the indexing model from the issue text.