feat(math,gui): add full euler rotation and developer camera tools

feat(math,gui): add full euler rotation and developer camera tools

Add yaw/pitch/roll Euler angle support to Quaternion and Transform,
enabling complete 3-axis camera orientation. The developer tools panel
now displays real-time camera position and rotation with a copy button
for saving viewpoints to source code.

Fix mouse drag to initialize from current camera orientation, preventing
jumps when camera was programmatically positioned with non-default
rotation.

Optimize alpha blending in rendering loops by replacing division with
bit-shift and pre-multiplying source colors. Add bounds clamping and
Arrays.fill optimization to TextureBitmap.fillRect.