lower takes the item's speaker; a referent citing it is printed with no entity,
and the speaker has no line in the entities map and is never looked up, so no
lowering prompt holds the speaker id (lower-prompt-no-item-text). Fixtures that
relied on a cited speaker now cite a prior-turn speaker. PROMPT_SOURCE_DIGEST
changes with context.rs.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
A referent citing the item's speaker puts that entity id in the packet JSON and
the entities map of the lowering prompt, against lower-prompt-no-item-text.
Fails on bf57192 at the speaker id assertion.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>