Phase 3 review identified an RBAC + cost-cap bypass: `SELECT * FROM
"bq"."ds"."tbl"` (catalog token quoted as a DuckDB identifier) was NOT
matched by the BQ_PATH regex, so direct quoted-form references skipped
both the registry check and the cost-cap dry-run. DuckDB resolves
`"bq"` to the same ATTACHed BQ catalog, so the bypass is real.
Widen the catalog-token alternation: `(?:"bq"|bq)` matches both forms.
Negative lookbehind `(?<![\w.])` still rejects look-alike prefixes
(`other_bq`, `my_bq`); the new "my_bq".ds.tbl negative test locks that
in alongside `other_bq.ds.tbl`.
Tests:
- 2 new positive cases in tests/test_query_bq_regex.py for the quoted
form (`"bq"."finance"."ue"` and uppercase `"BQ"."ds"."tbl"`).
- 1 new negative case rejecting `"my_bq".ds.tbl` so the quoted-form
widening doesn't open a different evasion.
- 1 new RBAC test in tests/test_api_query_rbac_bq_path.py: admin
hitting an unregistered quoted path returns the same
bq_path_not_registered 403 as the unquoted form.
All 33 Phase 3 tests pass after the fix.
77cdb65f76