SQL using only a full backtick path (`<proj>.<dataset>.<table>`) as the
table reference had neither bare name_lookups nor direct bq.ds.tbl matches,
so _rewrite_user_sql_for_bigquery_query's Skip 1 returned the original SQL
unchanged. DuckDB then rejected the backtick syntax locally with
"syntax error at or near `"" before the query ever reached BigQuery.
Detect _BACKTICK_FULL_PATH matches in the rewriter and include them in the
Skip 1 guard so the SQL gets wrapped in bigquery_query(). No identifier
rewrite is needed — backtick paths are already BQ-native and
_rewrite_bq_table_refs_to_native preserves them verbatim via its
backtick-split pass.
Closes#363
9f778251c3