Support Django 5.2

[simwr872]

Hello,
A suggestion for how to support Django 5.2.

• set_values() before add_annotation() since annotations now populate selected field.
• Reference implicitly annotated field before trying to resolve reference the normal way.
• Add annotations to cte table for selected fields not already annotated.

I modified 2 tests to explicitly select foreign key ID. In Django 5.2 foreign key ID's would be annotated to the foreign key name. Let me know if it is preferred to join on the foreign key name instead.

test_heterogeneous_filter_in_cte now works.

For some context, I asked a question in the Django forums: https://forum.djangoproject.com/t/selecting-primary-key-in-5-2/40215.

[simwr872]

I think I solved this with 9257e6b but I will leave the initial comment below.

---

Upon further tinkering, this does not fully solve 5.2 compatibility. Given the example:

cte = With.recursive(lambda cte: Region.objects.values("pk").union(cte.join(Region, parent=cte.col.pk).values("pk")))
queryset = cte.queryset().with_cte(cte)
print(queryset.query)

Difference between SQL generated pre/post 5.2:

@@ -1,8 +1,8 @@
 WITH RECURSIVE "cte" AS
-  (SELECT "region"."name"
+  (SELECT "region"."name" AS "pk"
    FROM "region"
-   UNION SELECT "region"."name"
+   UNION SELECT "region"."name" AS "pk"
    FROM "region"
    INNER JOIN "cte" ON "region"."parent_id" = ("cte"."name"))
-SELECT "cte"."name"
+SELECT "cte"."name" AS "pk"
 FROM "cte"

Which is invalid because the last select SELECT "cte"."name" column no longer exists (this PR would only swap out cte.name to cte.pk on the JOIN-clause). I need some help on how to fix this.