All components, specs, and the generated API client now use the new
DocumentListItem shape — flat access (item.title, item.sender) instead of
the removed item.document.* nesting.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Title rendering with originalFilename fallback, sender vs unknown
placeholder, tag buttons per document tag, bulk-select checkbox gated
on canWrite, archive chips visibility, snippet/summary visibility,
em-dash for missing date.
11 tests covering ~30 of the row's branches.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>