Lifts the three-chip-plus-"+N" tag row out of ThumbnailRow into a
standalone TagChipList component so the chip cap + overflow policy
lives in one place and can be reused on other surfaces (document
detail header is a candidate). ThumbnailRow drops from 110 to ~90
lines and no longer owns tag-slicing logic — it just asks for the
list with max=3.
Behavior is byte-identical: same data-testid, same max cap, same
"+N" overflow indicator. All ThumbnailRow row-level tag tests
continue to pass against the new composition.
Refs #305
Fixes @felixbrandt suggestion 1 from PR review
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
3b3b551d84