fix(a11y): stop section-header trailing controls letter-wrapping

Reported on device: the Domain section header's Note button rendered
vertically — "N o t e", one character per line in a screen-tall capsule —
at a larger (not even accessibility-tier) text size. Same pathology the
row badges had: text inside a squeezed HStack compresses to a
one-character column instead of the layout adapting.

Three-part fix, mirroring the proven row treatment:

- CollapsibleSectionView's header is now a ViewThatFits: title, trailing
  controls, and chevron on one line while they genuinely fit; otherwise
  the trailing controls drop below the title row. Applies to every
  section header, not just Domain.
- The Note and Track bordered buttons get .fixedSize() so their text can
  never letter-wrap — their natural width is what pushes the header onto
  its stacked layout.
- The "Tracked" pill becomes an icon-only indicator (eye in a tinted
  circle) — with Pin and Note beside it the full pill was the first thing
  to compress, and the word survives for VoiceOver via its label.

Enforced audit suite stays green (7 tests, 0 failures, floor runtime).
The post-lookup header state itself is not reachable by the harness — it
requires a live lookup — so on-device confirmation closes this out.

0 files changed, 0 insertions, 0 deletions