fix(mui): freeze loading state + button label during dialog close (Modal + ConfirmDialog)

On save/delete success the parent flips loading false a beat before the dialog finishes its fade-out, so the button flashed back to 'Uložit změny'/'Smazat'. Both dialogs now freeze the loading flag (and the label props) while open, so the closing dialog keeps showing 'Ukládám…'/'Pracuji…'. Same derive-state-from-props pattern as the title freeze.

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

src/admin/ui/ConfirmDialog.tsx

@@ -32,21 +32,27 @@ export default function ConfirmDialog({
   loading = false,
 }: ConfirmDialogProps) {
   useDialogScrollLock(isOpen);
-  // Freeze the shown title/message while closing, so the fade-out transition
-  // never flashes empty when the caller clears its source data (e.g. sets the
-  // selected row to null) at the same instant it closes the dialog. This is
-  // React's "adjust state from props during render" pattern: update only while
-  // open, keep the last values once closed. (Self-contained — callers can clear
-  // their data on close however they like.)
-  const [shown, setShown] = useState({ title, message });
-  if (isOpen && (shown.title !== title || shown.message !== message)) {
-    setShown({ title, message });
+  // Freeze content + label + loading while open, so neither the message NOR the
+  // confirm button label flips during the close fade-out (e.g. on confirm,
+  // `loading` goes false a beat before the dialog finishes closing — without
+  // this the button would flash back to "Smazat"/confirmText). React
+  // "adjust state from props during render": update only while open. Also keeps
+  // content from flashing empty when the caller clears its row on close.
+  const [shown, setShown] = useState({ title, message, confirmText, loading });
+  if (
+    isOpen &&
+    (shown.title !== title ||
+      shown.message !== message ||
+      shown.confirmText !== confirmText ||
+      shown.loading !== loading)
+  ) {
+    setShown({ title, message, confirmText, loading });
   }
 
   return (
     <Dialog
       open={isOpen}
-      onClose={loading ? undefined : onClose}
+      onClose={shown.loading ? undefined : onClose}
       disableScrollLock
       slotProps={{ paper: { sx: { borderRadius: 3 } } }}
     >
@@ -55,16 +61,16 @@ export default function ConfirmDialog({
         <DialogContentText>{shown.message}</DialogContentText>
       </DialogContent>
       <DialogActions sx={{ px: 3, pb: 2 }}>
-        <MuiButton onClick={onClose} color="inherit" disabled={loading}>
+        <MuiButton onClick={onClose} color="inherit" disabled={shown.loading}>
           {cancelText}
         </MuiButton>
         <MuiButton
           onClick={onConfirm}
           variant="contained"
           color={confirmVariant === "danger" ? "error" : "primary"}
-          disabled={loading}
+          disabled={shown.loading}
         >
-          {loading ? "Pracuji…" : confirmText}
+          {shown.loading ? "Pracuji…" : shown.confirmText}
         </MuiButton>
       </DialogActions>
     </Dialog>

src/admin/ui/Modal.tsx

@@ -39,20 +39,25 @@ export default function Modal({
   // Freeze the shown title/subtitle/submitText while closing, so the fade-out
   // never flashes the "create" variant when the caller clears `editingUser` on
   // close (React derive-state-from-props: update only while open).
-  const [shown, setShown] = useState({ title, subtitle, submitText });
+  // Freeze label-affecting props (incl. `loading`) while open, so neither the
+  // title/submitText NOR the loading state flips during the close fade-out
+  // (e.g. on save, `loading` goes false a beat before the dialog finishes
+  // closing — without this the button would flash back to "Uložit změny").
+  const [shown, setShown] = useState({ title, subtitle, submitText, loading });
   if (
     isOpen &&
     (shown.title !== title ||
       shown.subtitle !== subtitle ||
-      shown.submitText !== submitText)
+      shown.submitText !== submitText ||
+      shown.loading !== loading)
   ) {
-    setShown({ title, subtitle, submitText });
+    setShown({ title, subtitle, submitText, loading });
   }
 
   return (
     <Dialog
       open={isOpen}
-      onClose={loading ? undefined : onClose}
+      onClose={shown.loading ? undefined : onClose}
       fullWidth
       maxWidth={maxWidth}
       disableScrollLock
@@ -68,15 +73,15 @@ export default function Modal({
       </DialogTitle>
       <DialogContent>{children}</DialogContent>
       <DialogActions sx={{ px: 3, pb: 2 }}>
-        <MuiButton onClick={onClose} color="inherit" disabled={loading}>
+        <MuiButton onClick={onClose} color="inherit" disabled={shown.loading}>
           {cancelText}
         </MuiButton>
         <MuiButton
           onClick={onSubmit}
           variant="contained"
-          disabled={loading || submitDisabled}
+          disabled={shown.loading || submitDisabled}
         >
-          {loading ? "Ukládám…" : shown.submitText}
+          {shown.loading ? "Ukládám…" : shown.submitText}
         </MuiButton>
       </DialogActions>
     </Dialog>