v0.5.1 of rapier_physics

A high-performance 3D physics engine for Flutter, powered by Rapier (Rust/WASM). Changelog excerpt: #### 2026-08-21 - **Character Controller Jump**: Added a **Jump**button to the `CharacterControllerScene`demo, enabling vertical impulse-based jumping with on-screen UI controls. - **Joystick Input Improvements**: Refined joystick interaction in `CharacterControllerScene`with a configurable input…