Refactor eQSL batch update to operate on resolved primary keys instead of re-matching QSOs by time/callsign/band/mode. Eqslmethods_model now queries current eQSL status by COL_PRIMARY_KEY, builds update batches keyed by primary key, and returns updated_ids and duplicate_ids. This avoids re-querying with un-normalized ADIF modes, improves reliability (avoids CI3 affected_rows() pitfalls), and makes duplicate detection deterministic. EqslImporter was updated to enqueue qso_id for batch updates and to mark QSOs as Updated or Already received based on the returned ID lists.
Fixes a bug where the wrong array key was checked when determining if an eQSL was received. The code previously used $record['qsl_sent']; it now checks $record['eqsl_qsl_rcvd'] to set $qsl_rcvd (or an empty string) using config['eqsl_rcvd_mark'], ensuring imports correctly mark received eQSLs.
Add batch processing for eQSL imports/exports and introduce performance indexes. Bump migration_version to 248 and add Migration_add_eqsl_performance_indexes to create idx_eqsl_qslrdate and idx_eqsl_confirmation_match indexes to speed up eQSL queries and batch matching. Modify Eqsl controller to collect successful uploads and perform a single batch mark-as-sent update. Update EqslImporter to queue confirmations and run a single batch update at the end. Implement eqsl_update_batch() and eqsl_mark_sent_batch() in Eqslmethods_model to perform efficient batch DB operations and logging, reducing per-record queries for large eQSL operations.
