feat: add percentage detents and validate sheet props

[DanyKrk]

Adds responsive percentage-based detents, such as '45%' and '100%', alongside existing numeric and 'content' detents.
Percentages are resolved natively against the available sheet height and update automatically when the layout changes on both
iOS and Android.

This also introduces stricter prop validation:

• Detents must be non-empty, finite, non-negative, and use valid 0%–100% percentage syntax.
• index must be a finite integer within the detents array.
• Invalid values now throw descriptive JavaScript errors instead of being silently clamped.
• Native resolved-order validation remains in place.

Documentation and example screens were expanded to cover percentage detents, invalid props, and safely updating the index when changing the detents array.

[patrickmichalik]

Thanks!