fix(ci): repair test-type breakage from generated image actions

fix(ci): repair test-type breakage from generated image actions

The image-actions feature landed with an untyped fetch spy and an unknown
URL argument; newer vitest types surface both. Capture anchor downloads via
a typed mock implementation and coerce the probed block URL. Also add the
toolCallId/itemId fields to the Discord harness's stale local copies of the
onToolStart/onCommandOutput payload types (canonical type already has them).