fix: ADR-0035 4i(c) — don't pre-flag a self-referencing FK parent

A `CREATE TABLE` whose foreign key references the table being created
(`create table T (id int primary key, parent_id int references T(id))`)
parses and executes correctly, but the pre-submit schema-existence
diagnostic flagged the not-yet-created table as "no such table" — the FK
parent slot is `IdentSource::Tables`, and the target isn't in the schema
yet.

schema_existence_diagnostics now collects the CREATE TABLE target(s)
(`IdentSource::NewName`, role `table_name`) and exempts a `Tables`
reference matching one (case-insensitively) from the unknown-table flag.
A FK to a genuinely-unknown *other* table is still flagged.

Tests: self-ref FK not flagged; FK to an unknown other table still
flagged. Full suite 1915 passing / 0 failing / 1 ignored; clippy clean.

src/dsl/grammar/sql_create_table.rs

@@ -150,14 +150,12 @@ pub(crate) static CHECK_NODES: &[Node] = &[
 // endpoints; the `( <col> )` is optional (the bare `REFERENCES
 // <parent>` form resolves to the parent's PK at execution).
 
-// NOTE (4i): `IdentSource::Tables` existence-checks the parent — good
-// for the common case (a typo'd parent shows a pre-submit hint), but a
-// self-referencing FK (`references <self>` while creating `<self>`)
-// false-flags the not-yet-created table as unknown. Parse + execution
-// are correct (the self-ref is validated against the in-statement
-// columns); only the live typing indicator is briefly wrong. ADR-0035
-// §13 4i: teach the schema-existence diagnostic about the CREATE TABLE
-// target so the self-ref indicator stops lying.
+// `IdentSource::Tables` existence-checks the parent, so a typo'd parent
+// shows a pre-submit hint. A self-referencing FK (`references <self>`
+// while creating `<self>`) is NOT flagged: the schema-existence
+// diagnostic exempts a `Tables` reference matching the `CREATE TABLE`
+// target — the table being created in the same statement (ADR-0035 §4i c,
+// `schema_existence_diagnostics`'s `created_tables`).
 const FK_PARENT_TABLE: Node = Node::Ident {
     source: IdentSource::Tables,
     role: "fk_parent_table",