Replace 5 per-preference children files with a single
preference-registry.tsx that auto-generates CMDK children via factory
functions. Rewrite useUserPreferences from ~347 lines to ~160 lines by
deriving mutation dispatch, pending state, and optimistic values from
preference definitions.
Simplify settings-children.tsx and groups.tsx to iterate over
visiblePreferenceDefinitions instead of maintaining manual mappings.
Deleted: board.tsx, color-scheme.tsx, first-day-of-week.tsx,
search-engine.tsx, registry.ts
Net reduction: ~261 lines across 9 files.
Thomas Camlong
5501ee6a7d