c41bc5a99d
W-T3 (617477b) consolidated toast rendering into a single <ToastHost />
mounted in +layout.svelte, but page-level tests render components without
the layout, so screen.getByTestId('toast') and role=status queries broke.
Mount ToastHost in beforeEach (auto-cleaned by svelteTesting()) and reset
the store with clearToast() in afterEach so toasts can't leak between
tests.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>