fix(data-grid): sticky positioning for pinned columns in firefox (#1087)

* fix: optimize Firefox sticky positioning fix

- Inline Firefox detection in useDataGrid using useSyncExternalStore
- Pass isFirefox from hook down to components to avoid repeated checks
- Short-circuit pinned columns check when not Firefox
- Remove separate useIsFirefox hook file for simpler distribution

Closes #1082

* refactor: rename isFirefox to adjustLayout for clarity

- Renamed isFirefox prop to adjustLayout in DataGridRow
- Fixed logic bug: adjustLayout now correctly only true when Firefox AND columns are pinned
- Removed redundant comments, logic is self-documenting
- Cleaner, more semantic naming

* chore: rebuild registry

Author: sadmann7