fix: move save state updates to SavedDocument handler

Fixes #3558 - Cancelling document saving leads to content/modifications being lost

Previously, set_save_state(true) was called in the SaveDocument handler
before the save dialog even appeared. This caused the document to be
marked as saved even if the user cancelled the save dialog.

Now the save state updates (set_save_state, set_auto_save_state) are
called in the SavedDocument handler, which only executes after the file
has actually been written to disk. This ensures that:
- Cancelling the save dialog keeps the document marked as unsaved
- The asterisk indicator remains visible until the file is truly saved
- No content/modifications are lost if the save is cancelled

Author: theaniketgiri

editor/src/messages/portfolio/document/document_message_handler.rs

@@ -1046,11 +1046,6 @@ impl MessageHandler<DocumentMessage, DocumentMessageContext<'_>> for DocumentMes
 					self.path = None;
 				}
 
-				self.set_save_state(true);
-				responses.add(PortfolioMessage::AutoSaveActiveDocument);
-				// Update the save status of the just saved document
-				responses.add(PortfolioMessage::UpdateOpenDocumentsList);
-
 				responses.add(FrontendMessage::TriggerSaveDocument {
 					document_id,
 					name: format!("{}.{}", self.name.clone(), FILE_EXTENSION),
@@ -1061,7 +1056,12 @@ impl MessageHandler<DocumentMessage, DocumentMessageContext<'_>> for DocumentMes
 			DocumentMessage::SavedDocument { path } => {
 				self.path = path;
 
+				// Mark the document as saved now that the file has actually been written
+				self.set_save_state(true);
+				self.set_auto_save_state(true);
 				responses.add(PortfolioMessage::AutoSaveActiveDocument);
+				// Update the save status of the just saved document
+				responses.add(PortfolioMessage::UpdateOpenDocumentsList);
 
 				// Update the name to match the file stem
 				let document_name_from_path = self.path.as_ref().and_then(|path| {