fix(offers): deleting an order returns the source offer to active

deleteOrder only nulled quotations.order_id and left status "ordered" -
a dead end (ordered only transitions to invalidated), so the offer could
never be ordered again and the "Vytvorit objednavku" button stayed
hidden. The delete transaction now reverts ordered -> active together
with the back-reference clear; regression test included.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/services/orders.service.ts

@@ -761,7 +761,16 @@ export async function deleteOrder(id: number, deleteFiles = false) {
         }
       }
 
-      // Clear quotation back-reference (matching PHP)
+      // Clear the quotation back-reference AND revert its status: an
+      // `ordered` offer with no order is a dead end (the transition table
+      // only allows ordered -> invalidated), so it goes back to `active`,
+      // making it orderable again.
+      await tx.quotations.updateMany({
+        where: { order_id: id, status: "ordered" },
+        data: { order_id: null, status: "active", modified_at: new Date() },
+      });
+      // Backstop for rows in any other status (shouldn't exist — only an
+      // ordered offer can hold an order_id).
       await tx.quotations.updateMany({
         where: { order_id: id },
         data: { order_id: null },