feat(manifest): add externalNumber reference to quote/order/delivery

- Add `external_number NVARCHAR(100)` column to the `manifest` table.
- Thread `externalNumber` through manifestDoc and delivery SQL (list,
  header, create, update).
- Include `externalNumber` in shapeSummary and quote/order/delivery
  create/update/list/getById handlers (optional, clearable on update).
- Update README type definitions and regenerate API/schema docs.

src/store/manifestDoc/helpers.js

@@ -16,6 +16,7 @@ export function shapeSummary(type, row) {
     number: row.number,
     type,
     entityId: row.entityId ?? null,
+    externalNumber: row.externalNumber ?? null,
     date: row.date,
   };
 }