PersonTypeBadge: one test per switch arm (INSTITUTION, GROUP, UNKNOWN)
plus the two no-render branches (unrecognised type, empty type).
ExpandableText: clamp detection, toggle visibility logic, expand →
collapse round-trip, default maxLines fallback.
PersonChipRow: sender-only, sender+arrow, abbreviated naming, max-two
visible receivers, +N overflow pill presence/absence, receivers-only
case (no sender → no arrow).
19 tests across three files. Each file uses afterEach(cleanup) and
queries via getByRole/getByText so tests stay decoupled from CSS.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
