[Afloat16]

Summary

When the MCP initialization request times out, startAgentBrowserMcp attempts to kill the detached Vercel command before rejecting. If that cleanup request never resolves, the configured initialization timeout never reaches the caller.

Start the cleanup request without awaiting it and keep handling cleanup rejections. The caller receives the original initialization failure while the provider processes the kill request.

Validation

The validation results below were recorded for this branch against baseline e7519957b9067c541825afa21a792fbe1f483047.

• A stalled-kill regression fails on unchanged main because startup remains pending after the initialization timeout.
• The regression passes with this change; a second case verifies that a rejected kill preserves the original initialization error.
• TypeScript build and the full sandbox test suite pass: 29 tests.
• git diff --check passes.

[vercel]

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