Add migration to fix wrong GIDs

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/coredata/migrations/20260119T182800.sql

@@ -0,0 +1,9 @@
+UPDATE
+    iam_memberships m
+SET
+    id = generate_gid(decode_base64_unpadded(o.tenant_id), 39)
+FROM
+    organizations o
+WHERE
+    o.id = m.organization_id
+    AND extract_entity_type(parse_gid(m.id)) = 38;