fix(pfs): is_missing_table_error requires both Catalog and does-not-exist

Matching either substring alone could treat an unrelated error (e.g. a
file-not-found message that happens to say "does not exist") as "no
derived tables yet, nothing to do" and silently swallow a real bug.
Require both, as a real DuckDB Catalog error always carries both.

src/pfs/codetables.py

@@ -226,7 +226,7 @@ def is_missing_table_error(exc: Exception) -> bool:
     ``pfs.extract`` so every read-only CPT-table lookup treats a missing
     table the same way."""
     msg = str(exc)
-    return "Catalog" in msg or "does not exist" in msg
+    return "Catalog" in msg and "does not exist" in msg
 
 
 def ensure_tables(con: Any) -> None:

tests/pfs/test_codetables.py

@@ -12,6 +12,7 @@ from pfs.codetables import (
     ReviewRow,
     cpt_years,
     ensure_tables,
+    is_missing_table_error,
     read_all_elements,
     read_all_events,
     read_cpt_codes,
@@ -51,6 +52,27 @@ def _el(code="99490", value="consent", year=2015):
     )
 
 
+class TestIsMissingTableError:
+    def test_true_for_a_real_duckdb_catalog_error(self, con):
+        with pytest.raises(Exception) as exc_info:
+            con.execute("SELECT * FROM pfs.nope")
+        assert is_missing_table_error(exc_info.value)
+
+    def test_false_when_only_catalog_present(self):
+        assert not is_missing_table_error(Exception("Catalog Error: something else"))
+
+    def test_false_when_only_does_not_exist_present(self):
+        # A message that happens to say "does not exist" for an unrelated
+        # reason (not a Catalog error) must not be treated as "missing
+        # table, just nothing derived yet" — that would swallow a real bug.
+        assert not is_missing_table_error(Exception("file does not exist"))
+
+    def test_true_when_both_substrings_present(self):
+        assert is_missing_table_error(
+            Exception('Catalog Error: Table "pfs.code_family" does not exist')
+        )
+
+
 class TestDDL:
     def test_idempotent(self, con):
         ensure_tables(con)