INSERT OR REPLACE deletes the existing row and resets columns absent from
the VALUES list (predicted_rating, std_dev, last_round_update,
excluded_rounds_count, cutoff_rating) to NULL. Refresh-all called this for
every player, wiping predicted ratings table-wide.
Switch to a SQLite UPSERT keyed on pdga_number that updates only the four
scraped columns in place, leaving the predicted-rating columns and the
24h-cooldown timestamp untouched. Mirror course.js's lastID==0 SELECT
fallback so the function still returns a real player id on the update path.
Samuel Enocsson