Barrier Trials Copy

Copies tblbarriertrials from the source database into trial_meeting, trial_race, and trial_run in the destination. Uses the Excel field mapping file to drive column mappings. Foreign keys (course, runner, jockey, trainer, country) are resolved from existing config_id_mappings — no duplicate records are created.

Must contain sheets: tblbarriertrials → trial_meeting, tblbarriertrials → trial_race, tblbarriertrials → trial_run.

Truncates trial_meeting, trial_race, trial_run and removes config_id_mappings. Use before a full re-run.