Refactors the callsign/gridsquare search to support exact match toggling, partial/broad match fallback, and a recent searches history stored in localStorage. Search terms are now passed via GET parameters (bookmarkable URLs) instead of POST. The advanced filter panel gains result count badges, a clear button, and persists query rules across page loads. DataTable initialization is extracted into reusable helpers.
Add a cached DXCC lookup and a jsondxcc endpoint to speed up country resolution and reduce DB load (file-cache with 1h TTL). Introduce cached_dxcc_lookup(), build_confirmation_where(), and callsign_status() in the Logbook controller; refactor confirmed_grid_before() and worked_grid_before() to accept logbook relationships and confirmation prefs to avoid redundant queries. Use a new Logbook_model::get_recent_callsign_details() to populate recent name/gridsquare/qth/iota/qsl/state/county values in a single query. Update JS to better manage lookup state, invalidate in-flight requests, and perform a debounced quick DXCC lookup to improve UX. Tweak previous-contacts pagination to a compact sliding window and remove a redundant UI note.
Enhanced the QSO access logic to allow access if the QSO belongs to the user or is part of a user's active logbook, including shared permissions. Added a guard in the controller to prevent accessing missing or inaccessible QSOs, redirecting with a notice if access is denied.
Wrapped assignments of 'dxcc_name' with checks to ensure the entity is an array and contains a 'name' key. This prevents potential errors if the entity lookup fails or returns unexpected data.
Adds a check to ensure that if a QSO is not found or not accessible, the user is redirected to the dashboard with a notice. This prevents errors when attempting to access non-existent or unauthorized QSOs.
