Replace ad-hoc xss_clean calls with explicit casting and stronger type checks for ID/parameter handling, and convert many raw SQL strings to CodeIgniter Query Builder usage. Added normalize_location_ids helpers (Activators_model, Oqrs_model) to safely parse location lists and used where_in/parameter binding/escaping to avoid injection and improve maintainability. Also adjusted session user_id handling, improved LIKE/DATE/TIMEDIFF usage, and tightened several model/controller methods (Labels, Activators, Bands, Contesting, Labels_model, Modes, Oqrs_model, Qsl_model, Setup_model, Sstv_model, User_model) for safer, clearer DB queries and inputs.
Replaces standard callsign ordering with natural sorting by splitting callsigns into prefix, number (padded), and suffix. This improves the order of QSO label results for better readability and organization.
