Platform Feature Flow

Trace a file export feature from UI to platform.

Flow

Export button
  -> ExportViewModel.exportCsv()
  -> ExpensesRepository.loadForExport()
  -> CsvExporter.createFile()
  -> PlatformShareService.shareFile()
  -> plugin or platform channel
  -> Android/iOS/desktop/web implementation
  -> target smoke test

Test Points

Point	Test
View model	Export command handles loading, success, and failure
Repository	Returns correct rows and sort order
Exporter	Produces stable CSV with escaping
Platform service	Fake in unit/widget tests
Plugin/channel	Integration or manual smoke on each target
Release	Export works from release artifact, not only debug

Unsupported Target Path

If web export is not supported by the chosen plugin, the app should show a clear fallback or hide the feature on web. Do not let a MissingPluginException be the user experience.