fixed overwrite on internal copy, DST drift in widget anchors, inline errors without controller and removed dead room lookup

lib/share_intent/internal_share_actions.dart

@@ -7,8 +7,8 @@ import 'remote_file_ref.dart';
 
 /// Server-side WebDAV copy of [source] into [targetFolderPath]. On a 412
 /// conflict the user is asked whether to overwrite; on confirmation the call
-/// is retried with `overwrite: true`. Returns true when the file ended up at
-/// the target, false when the user cancelled.
+/// is retried with `overwrite: true` inside the dialog. Returns true when the
+/// file ended up at the target, false when the user cancelled.
 Future<bool> copyRemoteFileTo({
   required BuildContext context,
   required RemoteFileRef source,
@@ -27,19 +27,11 @@ Future<bool> copyRemoteFileTo({
   } on DynamiteApiException catch (e) {
     if (e.statusCode != 412) rethrow;
     if (!context.mounted) return false;
-    final overwrite = await showDialog<bool>(
-      context: context,
-      builder: (ctx) => ConfirmDialog(
-        title: 'Datei existiert bereits',
-        content:
-            '"${source.name}" existiert in /$targetFolderPath. Überschreiben?',
-        confirmButton: 'Überschreiben',
-        cancelButton: 'Abbrechen',
-        onConfirm: () => Navigator.of(ctx).pop(true),
-      ),
-    );
-    if (overwrite != true) return false;
-    await webdav.copy(src, dstUri, overwrite: true);
-    return true;
+    return ConfirmDialog(
+      title: 'Datei existiert bereits',
+      content: '"${source.name}" existiert in /$targetFolderPath. Überschreiben?',
+      confirmButton: 'Überschreiben',
+      onConfirmAsync: () => webdav.copy(src, dstUri, overwrite: true),
+    ).ask(context);
   }
 }