CNTabBar taps were silently swallowed whenever an ancestor widget held
an active gesture recognizer over the same region (e.g. requests_inspector
wrapping the app in GestureDetector(onLongPress:)). The platform views
were constructed without a gestureRecognizers set, making them passive
arena participants.

Both the iOS UiKitView and macOS AppKitView branches now pass an
EagerGestureRecognizer, which resolves accepted on pointer-down so
touches forward to the native UITabBar regardless of competition.

Merged from PR #63 by @MohamedAboElM3aTy, amended before merge: the
submitted bare TapGestureRecognizer() is a no-op because Flutter's
isPointerAllowed returns false when no callbacks are set.

Also formats tab_bar.dart (contributor indentation broke dart format
and cost 10 pana points).

Follow-up sweep for the remaining components tracked in #65.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>