performance-optimization

Replace unbounded Column plus children with ListView.builder, SliverList, or sliver composition so only visible items build lazily. Use fixed-height rows where possible, and only tune cacheExtent after profiling shows a measurable benefit.

Use ref.watch(provider.select(...)) to subscribe only to the fields a widget needs instead of entire state objects. Split providers by update frequency, such as separating price ticks from static config, and avoid ref.watch in leaf widgets that need one field.

Run flutter run --profile from the flutter_app directory and open Flutter DevTools to inspect the Performance tab, timeline, and rebuild stats. Reproduce the lag on a specific device, route, and action, then cite a metric like frame time or rebuild count before changing code.

Wrap custom painters such as chart painters in a RepaintBoundary when the parent rebuilds frequently, so the painted layer is isolated. Keep shouldRepaint precise so repaints only occur when the underlying data actually changes.

Do not optimize speculatively when no plan gate requires it and no measurable problem exists. The workflow requires reproduction and a cited metric first, so premature optimization without profiling evidence is explicitly out of scope.