feat: implement 3D spatial audio, boss SFX, and optimize audio loading
- Add Snd3d class for spatialized audio with distance attenuation and panning.
- Rename SoundWave to SndWav and integrate with audio sinks in Scene/Gameplay.
- Implement Crystal Sanctuary Guardian SFX: attack, damage, death, intro barks, and animation-synced footsteps.
- Optimize audio loading by removing the normalization pass and reusing buffers.
- Improve SkMesh::getAnimTime for precise animation-to-SFX synchronization.
- Add Bitwig source projects and raw WAV assets for new sound effects.
- Create doc/journal.md and update doc/todo.md with progress on rendering and boss completion.
- Update .gitignore to exclude auto-backups.