- SortControl no longer renders a blank select when an always-sorted view
(no defaultLabel) is handed a key its options don't offer: it falls back to
the first option instead of value="" (which also tripped React's controlled
warning). Robustness now lives in the primitive, not each caller.
- PLEX_SORT_FALLBACK is Object.frozen: it's handed out by reference from
healSort/healPlexSort and stored as provider state, so freezing turns any
accidental in-place SortState mutation into a loud error instead of silently
corrupting the shared fallback.
- Test: SortControl falls back to the first option for an unavailable key.
Gate green: tsc/eslint(0 err)/prettier/knip clean, vitest 106.
peter
ccd7170a20