Function adjust_trust_radius 

pub fn adjust_trust_radius(
    state: &mut OptimizationState_blend,
    current_e1: f64,
    config: &Config,
)

Adjusts the trust radius based on the actual energy change from QM.

Uses a simple heuristic:

• If energy increased significantly (> 0.0001 Ha): halve trust radius
• If energy decreased (> 0.0001 Ha): increase trust radius by 20%
• Otherwise: keep unchanged

Updates both trust_radius and prev_e1 in the state.

Arguments

• state - Mutable optimization state to update.
• current_e1 - E1 energy from the most recent QM calculation.
• print_level - Print level (0=quiet, 1=normal, 2=verbose).