* Add success toast after saving diagram
* fix: correct save toast placement
* Changes made:
1. Added i18n support
2. Fixed the issue where the save toast was running only once
* fix: show toast after download completes, not when dialog opens
Move toast from handleDrawioSave (dialog open) to saveDiagramToFile
(after download). Also restore the duplicate-save guard that was removed.
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Co-authored-by: Biki Kalita <[email protected]>
Co-authored-by: dayuan.jiang <[email protected]>
