Review Flutter package code

Review Flutter code for modern Dart patterns and architecture compliance

When validating Flutter widgets use modern key passing, typedefs, and switch expressions

• · Flutter code diff

• · Style violations
• · Modernization suggestions

Flutter/Dart 3.0+ language features available; widget architecture conventions established

• · Widgets use legacy Key? key pattern instead of super parameter
• · typedef syntax uses old Function type instead of modern syntax
• · switch statements used instead of switch expressions

• · Includes test/validation protocols
• · Explicit error handling
• · Provides usage examples
• · Built on formal specifications