feat(po): add additional_attachments to PurchaseOrder type

src/lib/types.ts

@@ -726,6 +726,17 @@ export interface PurchaseOrder extends BaseRecord {
    * Replaces the legacy `purchase_order_pdfs` collection.
    */
   documents?: string[];
+  /**
+   * Files attached to the PO for the supplier (supplier quote, drawing,
+   * NDA, etc.). Sent alongside the versioned PO PDF on email. Distinct
+   * from `documents`, which is the versioned-PDF history; mixing the two
+   * breaks the `documents ↔ documents_history` invariant the PDF download
+   * path depends on.
+   *
+   * PB file field, multi, no PB-side cap. The upload route enforces
+   * 25 MB per file to match the rest of the app.
+   */
+  additional_attachments?: string[];
   /**
    * Audit log of every document that has ever lived on this PO.
    * Mirrors the structure of the legacy `purchase_order_pdfs` row