Function export_hmm_transition_probabilities 

pub fn export_hmm_transition_probabilities<P: AsRef<Path>>(
    debug_info: &DebugInfo,
    output_path: P,
) -> Result<(), ProjectionError>

Export Phase 2 – HMM transition probabilities as GeoJSON

Produces a FeatureCollection with one LineString feature per feasible (non-zero) candidate-pair transition across consecutive GNSS observations. Each feature links the projected point of the preceding candidate to the projected point of the succeeding candidate, so that connectivity gaps and long transitions stand out visually.

Only transitions with a non-zero probability are included; impossible transitions (disconnected network paths, edge-zone constraints) are omitted.

Properties per feature:

• from_step – observation index of the preceding position (0-based)
• to_step – observation index of the succeeding position (0-based)
• from_netelement_id – netelement of the preceding candidate
• to_netelement_id – netelement of the succeeding candidate
• transition_probability – linear-scale transition probability [0, 1]
• is_viterbi_chosen – whether this pair was chosen by the Viterbi algorithm