Adds a check for zero QSOs in the statistics section. Displays an informational alert and hides tabs when no QSOs are found, improving user feedback for new users.
Introduces new summary statistics, trends, continent, and most worked data endpoints to Statistics controller, with corresponding AJAX and UI updates in statistics.js and index.php. Adds summary cards, date range filtering, error handling, and improved chart/table rendering for a more interactive statistics dashboard.
