Function compile_native_observation_quins 

pub fn compile_native_observation_quins(
    media_hash: u64,
    media_byte_len: u64,
    model_hash: u64,
    detections: &[NativeDetection],
    out: &mut [NQuin],
) -> Result<usize, VisionError>

Compile native detections into epistemic NQuins (caller buffer). Writes model digest + per-det observation/class/bbox/track. Returns count.