fix: avoid freeze on very fast repeated swipes

[ncthuc2004]

Summary

• prevent repeated swipe transitions from starting while a previous tab transition is still resolving
• guard both swipe gesture handling and tab selection with isTransitionInProgress
• reset the guard when transition completes or when no transition starts

Why

Issue #52 reports app freezes during very fast repeated swipes. The change serializes swipe-driven transitions to avoid re-entrant state updates.

Testing

• Reasoned from transition lifecycle in SwipeableTabBarController
• No iOS simulator available in this environment

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IssueHunt Summary

Referenced issues

This pull request has been submitted to:

• #52: Very quick swipes cause app to freeze

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