Move logs from array to dedicated table

This avoids the append problem which bloats the database to 200+ gb in a
month and shrinks again to 5g with a full vacuum

server/upload.go

@@ -213,7 +213,7 @@ func errorUpload(r *http.Request, w http.ResponseWriter, taskID int, msg string,
 	slog.ErrorContext(r.Context(), msg, "err", err)
 	http.Error(w, msg+": "+err.Error(), http.StatusInternalServerError)
 	if taskID != 0 {
-		_, err2 := db.Exec(context.TODO(), "UPDATE tasks SET log = log || $2 WHERE id = $1", taskID, []string{fmt.Sprintf("%v MASTER: upload error: "+msg+": "+err.Error(), time.Now())})
+		_, err2 := db.Exec(context.TODO(), "INSERT INTO logs(task_id, message) VALUES($1,$2)", taskID, fmt.Sprintf("%v MASTER: upload error: "+msg+": "+err.Error(), time.Now()))
 		if err != nil {
 			slog.ErrorContext(r.Context(), "Updating task log with upload error", "err", err2)
 		}