fix(ui): guard delete on paid invoices / ordered-or-locked offers; add guarded delete to issued orders

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/pages/InvoiceDetail.tsx

@@ -1211,15 +1211,19 @@ export default function InvoiceDetail() {
                   Zobrazit fakturu
                 </Button>
               )}
-              {hasPermission("invoices.delete") && (
-                <Button
-                  onClick={() => setDeleteConfirm(true)}
-                  variant="outlined"
-                  color="error"
-                >
-                  Smazat
-                </Button>
-              )}
+              {/* A paid invoice is a settled financial record — never deletable
+                  from the UI. (Backend rejection of deleting a paid invoice is a
+                  separate hardening, out of scope here.) */}
+              {hasPermission("invoices.delete") &&
+                invoice.status !== "paid" && (
+                  <Button
+                    onClick={() => setDeleteConfirm(true)}
+                    variant="outlined"
+                    color="error"
+                  >
+                    Smazat
+                  </Button>
+                )}
             </Box>
           </Box>
         </Box>
@@ -1778,15 +1782,20 @@ export default function InvoiceDetail() {
                       )}
                     </Button>
                   ))}
-                {hasPermission("invoices.delete") && (
-                  <Button
-                    onClick={() => setDeleteConfirm(true)}
-                    variant="outlined"
-                    color="error"
-                  >
-                    Smazat
-                  </Button>
-                )}
+                {/* A paid invoice is a settled financial record — never
+                    deletable from the UI. A paid invoice never actually reaches
+                    this branch (it renders the read-only view above), but the
+                    guard documents the invariant explicitly. */}
+                {hasPermission("invoices.delete") &&
+                  invoice.status !== "paid" && (
+                    <Button
+                      onClick={() => setDeleteConfirm(true)}
+                      variant="outlined"
+                      color="error"
+                    >
+                      Smazat
+                    </Button>
+                  )}
               </>
             )}
           </Box>

src/admin/pages/IssuedOrderDetail.tsx

@@ -540,6 +540,8 @@ export default function IssuedOrderDetail() {
     status: string | null;
   }>({ show: false, status: null });
   const [pdfLoading, setPdfLoading] = useState(false);
+  const [deleteConfirm, setDeleteConfirm] = useState(false);
+  const [deleting, setDeleting] = useState(false);
 
   // ─── Queries ───
   const customersQuery = useQuery(offerCustomersOptions());
@@ -654,6 +656,12 @@ export default function IssuedOrderDetail() {
     invalidate: ["issued-orders"],
   });
 
+  const deleteMutation = useApiMutation<void, unknown>({
+    url: () => `${API_BASE}/issued-orders/${id}`,
+    method: () => "DELETE",
+    invalidate: ["issued-orders"],
+  });
+
   // ─── Item handlers ───
   const updateItem = (
     index: number,
@@ -768,6 +776,21 @@ export default function IssuedOrderDetail() {
     }
   };
 
+  // ─── Delete ───
+  const handleDelete = async () => {
+    setDeleting(true);
+    try {
+      await deleteMutation.mutateAsync(undefined);
+      alert.success("Objednávka byla smazána");
+      navigate("/orders?tab=vydane");
+    } catch (err) {
+      alert.error(err instanceof Error ? err.message : "Chyba připojení");
+    } finally {
+      setDeleting(false);
+      setDeleteConfirm(false);
+    }
+  };
+
   // ─── PDF export ───
   const handleViewPdf = async () => {
     const newWindow = window.open("", "_blank");
@@ -901,6 +924,21 @@ export default function IssuedOrderDetail() {
                 )}
               </Button>
             ))}
+          {/* A completed order is terminal/finalized — never deletable from the
+              UI. draft/sent/confirmed/cancelled may be deleted. (Backend
+              rejection of deleting an order is a separate hardening, out of
+              scope here.) */}
+          {isEdit &&
+            hasPermission("orders.delete") &&
+            form.status !== "completed" && (
+              <Button
+                onClick={() => setDeleteConfirm(true)}
+                variant="outlined"
+                color="error"
+              >
+                Smazat
+              </Button>
+            )}
         </Box>
       </Box>
 
@@ -1280,6 +1318,21 @@ export default function IssuedOrderDetail() {
           }
         />
       )}
+
+      {/* Delete confirm */}
+      {isEdit && (
+        <ConfirmDialog
+          isOpen={deleteConfirm}
+          onClose={() => setDeleteConfirm(false)}
+          onConfirm={handleDelete}
+          title="Smazat objednávku?"
+          message={`Opravdu chcete smazat objednávku "${poNumber}"? Tato akce je nevratná.`}
+          confirmText="Smazat"
+          cancelText="Zrušit"
+          confirmVariant="danger"
+          loading={deleting}
+        />
+      )}
     </PageEnter>
   );
 }

src/admin/pages/OfferDetail.tsx

@@ -663,6 +663,11 @@ export default function OfferDetail() {
   const isLockedByOther = !!lockedBy;
   const readOnly = isInvalidated || isLockedByOther || isCompleted;
   const canInvalidate = isEdit && !isInvalidated && !isCompleted && !orderInfo;
+  // An offer is deletable only when it has NOT spawned an order (orderInfo —
+  // deleting would orphan the linked order), is NOT invalidated, and is NOT
+  // locked by another user. (Backend rejection of deleting an ordered offer is
+  // a separate hardening, out of scope here.)
+  const canDelete = isEdit && !orderInfo && !isInvalidated && !isLockedByOther;
 
   // Sync offer detail data to form state on first load (edit mode)
   const formInitializedRef = useRef(false);
@@ -1190,7 +1195,7 @@ export default function OfferDetail() {
                 {saving ? "Ukládání..." : "Uložit"}
               </Button>
             )}
-            {isEdit && hasPermission("offers.delete") && (
+            {canDelete && hasPermission("offers.delete") && (
               <Button
                 onClick={() => setDeleteConfirm(true)}
                 variant="outlined"