refactor: pipeline automation

[mosure]

• bevy 0.15 support
• bevy_interleave planar macros
• gaussian 2d
• gaussian 3d
• gaussian 4d
• multiple gaussian types in a single scene
• modular pipeline components
• gc4d io (ply-export https://gist.github.com/mosure/d9d4d271e05a106157ce39db62ec4f84)
• gaussian compute node /w sort/vertex node passthrough
• gaussian 4d web demo
• spacetime gaussians
• quantized gaussian variants
• webgl (planar texture) support

cargo run -- --gaussian-mode gaussian4d

minimal setup for new planar formats:

#[derive(
    Clone,
    Debug,
    Default,
    Copy,
    PartialEq,
    Planar,
    ReflectInterleaved,
    StorageBindings,
    Reflect,
    Pod,
    Zeroable,
    Serialize,
    Deserialize,
)]
#[repr(C)]
pub struct Gaussian4d {
    pub isomorphic_rotations: IsotropicRotations,
    pub position_visibility: PositionVisibility,
    pub scale_opacity: ScaleOpacity,
    pub spherindrical_harmonic: SpherindricalHarmonicCoefficients,
    pub timestamp_timescale: TimestampTimescale,
}

what is next?

• cloud 4d hierarchy