Bug type

Regression (worked before, now fails)

Summary

Commit 8e4a1d8 (#45824) switched tts-core.ts from resolveModel (sync) to resolveModelAsync but did not update the vi.mock in tts.test.ts. The mock only exports resolveModel, so vitest throws:

No "resolveModelAsync" export is defined on the "../agents/pi-embedded-runner/model.js" mock.

This causes Windows CI shard 3/6 to fail on any PR rebased onto latest main.

Steps to reproduce

1. Rebase any PR onto current main (includes 8e4a1d8)
2. Run pnpm test — src/tts/tts.test.ts fails

Fix

Add resolveModelAsync to the mock factory and update the two summarizeText test expectations from resolveModel → resolveModelAsync.

PR incoming.