queryer: don't emit a parent type-bound for reified-relationship properties

A SINGLE reified-relationship property (e.g. invoice.counterparty,
person.primary_contact — a property whose type is a relationship
subtype) is hydrated by a correlated subquery that joins the
relationship table and correlates source_id/target_id = parent.id; its
discriminators (the relationship subtype and the target's type CASE)
are constrained INSIDE that subquery.

For such a property the resolved edge is a REVERSE traversal
(forward = false) over a generic relationship FK
(fk_relationship_source_entity, destination = entity). compile_
polymorphic_bounds then took the `!edge.forward` branch with
poly_col = destination_columns[1] = "type" and
table_to_alias = "entity", which resolves to the PARENT's entity alias
— emitting a bound like `entity_1.type = 'counterparty'` into the
parent WHERE. No parent row has that type, so EVERY parent was dropped
(e.g. get_invoice returned null for an existing invoice whose
counterparty edge was absent).

Array reified traversals (contacts, occupancies) never hit this: an
array property has no bound_type_name. Only the single form did, and it
was previously unexercised.

Fix: in compile_polymorphic_bounds, skip the bound when the property's
resolved type is itself a relationship (type_def.relationship) — there
is no parent-row discriminator column to bound.

Test: new queryer case (person.primary_contact, type=contact) asserts
the parent WHERE has no spurious entity.type bound while the subquery
keeps its discriminator + source_id correlation. Full suite green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/queryer/compiler.rs

@@ -604,6 +604,17 @@ impl<'a> Compiler<'a> {
             if let Some(type_name) = bound_type_name {
               // Ensure this type actually exists
               if let Some(type_def) = self.db.types.get(&type_name) {
+                // A reified-relationship property (e.g. invoice.counterparty, person.primary_contact)
+                // is hydrated by a correlated subquery that joins the relationship table and correlates
+                // source_id/target_id = parent.id; its discriminators (the relationship subtype and the
+                // target's type CASE) are constrained INSIDE that subquery. There is no parent-row column
+                // to bound here — emitting one wrongly constrains the PARENT entity's own `type` column
+                // (e.g. `entity_1.type = 'counterparty'`), which no parent row satisfies, dropping every
+                // parent. (Array reified traversals never reach this code: an array prop has no
+                // bound_type_name.) So skip the bound entirely for relationship-typed properties.
+                if type_def.relationship {
+                  continue;
+                }
                 if let Some(relation) = self.db.relations.get(&edge.constraint) {
                   let mut poly_col = None;
                   let mut table_to_alias = "";