Function calculate_advanced_stability 

pub fn calculate_advanced_stability(
    mass_grains: f64,
    velocity_fps: f64,
    twist_rate_inches: f64,
    caliber_inches: f64,
    length_inches: f64,
    air_density_kg_m3: f64,
    temperature_k: f64,
    bullet_type: &str,
    has_boat_tail: bool,
    has_plastic_tip: bool,
) -> f64

Calculate advanced Miller stability with modern corrections.

has_plastic_tip is retained for source compatibility, but a Boolean cannot provide the tip length required by the Courtney-Miller correction. No plastic-tip scalar is applied here; use apply_courtney_miller_plastic_tip_correction on this result when tip length is known.

air_density_kg_m3 is the resolved density for the complete atmospheric state. The temperature_k argument is retained for source compatibility but is not applied separately; callers changing temperature must supply the corresponding density.