simplify: dedupe boilerplate and remove dead code across all layers

lib/view/pages/share_intent/share_chat_picker.dart

@@ -166,13 +166,24 @@ Future<void> _afterExternalFilesUploaded(
   GetRoomResponseObject room,
   List<String> uploadedRemotePaths,
   PendingShare share,
-) async {
+) => _runShareFlow(
+  context,
+  action: () =>
+      shareFilesToChat(token: room.token, remoteFilePaths: uploadedRemotePaths),
+  onSuccess: () => _setExternalDraftAndOpenChat(context, room, share),
+);
+
+/// Shared share-flow scaffolding: shows the blocking spinner, runs [action],
+/// maps failures to an error dialog (popping the spinner first), and invokes
+/// [onSuccess] on success while still mounted.
+Future<void> _runShareFlow(
+  BuildContext context, {
+  required Future<void> Function() action,
+  required VoidCallback onSuccess,
+}) async {
   unawaited(_showBlockingSpinner(context));
   try {
-    await shareFilesToChat(
-      token: room.token,
-      remoteFilePaths: uploadedRemotePaths,
-    );
+    await action();
   } catch (e) {
     if (context.mounted) Navigator.of(context).pop();
     if (context.mounted) {
@@ -186,7 +197,7 @@ Future<void> _afterExternalFilesUploaded(
     return;
   }
   if (!context.mounted) return;
-  _setExternalDraftAndOpenChat(context, room, share);
+  onSuccess();
 }
 
 void _setExternalDraftAndOpenChat(
@@ -213,61 +224,30 @@ Future<void> _internalShareFlow(
   BuildContext context,
   GetRoomResponseObject room,
   RemoteFileRef file,
-) async {
-  unawaited(_showBlockingSpinner(context));
-  try {
-    await shareFilesToChat(
-      token: room.token,
-      remoteFilePaths: [file.path],
-    );
-  } catch (e) {
-    if (context.mounted) Navigator.of(context).pop();
-    if (context.mounted) {
-      InfoDialog.show(
-        context,
-        errorToUserMessage(e),
-        title: 'Fehler',
-        copyable: true,
-      );
-    }
-    return;
-  }
-  if (!context.mounted) return;
-  _finishWithChat(context, room);
-}
+) => _runShareFlow(
+  context,
+  action: () =>
+      shareFilesToChat(token: room.token, remoteFilePaths: [file.path]),
+  onSuccess: () => _finishWithChat(context, room),
+);
 
 Future<void> _forwardMessageFlow(
   BuildContext context,
   GetRoomResponseObject room,
   String? text,
   RemoteFileRef? file,
-) async {
-  unawaited(_showBlockingSpinner(context));
-  try {
+) => _runShareFlow(
+  context,
+  action: () async {
     if (file != null) {
-      await shareFilesToChat(
-        token: room.token,
-        remoteFilePaths: [file.path],
-      );
+      await shareFilesToChat(token: room.token, remoteFilePaths: [file.path]);
     }
     if (text != null && text.isNotEmpty) {
       await SendMessage(room.token, SendMessageParams(text)).run();
     }
-  } catch (e) {
-    if (context.mounted) Navigator.of(context).pop();
-    if (context.mounted) {
-      InfoDialog.show(
-        context,
-        errorToUserMessage(e),
-        title: 'Fehler',
-        copyable: true,
-      );
-    }
-    return;
-  }
-  if (!context.mounted) return;
-  _finishWithChat(context, room);
-}
+  },
+  onSuccess: () => _finishWithChat(context, room),
+);
 
 /// Modal progress overlay shown during share-API roundtrips. The dialog is
 /// popped together with the picker by the subsequent popUntil(isFirst).