The five `mock.ExpectQuery(\`SELECT id FROM workspaces\`)` sites used a
loose substring regex that silent-passed three regression shapes #2872
called out:
1. `WHERE parent_id = $2` (drops `IS NOT DISTINCT FROM` — breaks
NULL-parent root matching)
2. `WHERE name = $1` only (drops parent_id check entirely — hijacks
siblings of the same name across different parents)
3. Drops `AND status != 'removed'` (blocks re-import after Collapse)
Extracts a `lookupChildSQLRE` const that anchors all four load-bearing
tokens (the SELECT/FROM, the name predicate, the IS NOT DISTINCT FROM
predicate, and the status filter). All five ExpectQuery sites now use
the same const so a future schema/predicate change fails one place.
Mutation-tested per memory feedback_assert_exact_not_substring.md:
- Replacing `IS NOT DISTINCT FROM` with `=` fails
TestLookupExistingChild_NilParent_MatchesRoot.
- Dropping `AND status != 'removed'` fails
TestLookupExistingChild_Found_ReturnsIDAndTrue.
Note: #2872 PR-A (AST gate strengthening) is already addressed inline —
findWorkspacesInsertSQL + TestCreateWorkspaceTree_InsertUsesOnConflictDoNothing
pin the ON CONFLICT DO NOTHING shape, which is a strictly stronger
gate than the original lookup-before-insert ordering check.
Hongming Wang