refactor: centralized the iam seeder

packages/iam-seed/src/missing-settings.util.ts

@@ -0,0 +1,20 @@
+/**
+ * Settings of `ownerId` that are not in `existingPairs` (`"<ownerId>:<key>"`)
+ * yet. This is what keeps the IAM baseline seed idempotent: `organization_settings`
+ * and `unit_settings` have no unique index on (owner, key), so a plain re-insert
+ * — or the package seeder's upsert-on-id, which never supplies an id — silently
+ * duplicates every row.
+ *
+ * `value: null` becomes `undefined` so the column default applies on insert.
+ */
+export function missingSettings<
+  TSetting extends { key: string; value?: string | null },
+>(
+  defaults: TSetting[],
+  existingPairs: Set<string>,
+  ownerId: string,
+): (Omit<TSetting, "value"> & { value?: string })[] {
+  return defaults
+    .filter((setting) => !existingPairs.has(`${ownerId}:${setting.key}`))
+    .map((setting) => ({ ...setting, value: setting.value ?? undefined }));
+}