feat!: migrate pin_code_fields 10.0.0 to Flutter 3.47 material_ui

[bazookon]

Summary

Migrate pin_code_fields to Flutter 3.47's standalone design-system packages and release it as 10.0.0.

Flutter 3.47 publishes material_ui and cupertino_ui as 1.0 packages on pub.dev, decoupling Material and Cupertino from the core SDK. The Flutter team asks ecosystem packages that switch to these libraries to treat it as a major release. See What's new in Flutter 3.47.

The PIN field API (MaterialPinField, PinInput, PinInputController, MaterialPinTheme, etc.) is unchanged. This is an import / dependency migration.

Breaking changes

• Imports move from package:flutter/material.dart / package:flutter/cupertino.dart to package:material_ui/material_ui.dart / package:cupertino_ui/cupertino_ui.dart.
• New dependencies: material_ui: ^1.0.0, cupertino_ui: ^1.0.0.
• Minimum SDK: Dart ^3.12.0, Flutter >=3.44.0 (tested on Flutter 3.47.1 / Dart 3.13.1).
• Apps that still use SDK Material must migrate or wrap mixed trees with MaterialUiCompatibilityBridge. Mixing ThemeData from the SDK with ThemeData from material_ui can cause type mismatches.

Consumer migration

dependencies:
  pin_code_fields: ^10.0.0
  material_ui: ^1.0.0

flutter pub get
dart fix --apply --code=migrate_design_widgets

If other packages still import package:flutter/material.dart:

MaterialApp(
  builder: (context, child) {
    return MaterialUiCompatibilityBridge(child: child!);
  },
)

Full guide: packages/pin_code_fields/migration/10.0.0/MIGRATION_GUIDE.md.

What changed in this PR

• Bump package version 9.4.0 → 10.0.0.
• Switch library, example, and tests to material_ui / cupertino_ui.
• Pin published constraints (^1.0.0) instead of any.
• Raise environment constraints to match material_ui.
• Document the migration in the changelog, README, and a 10.0.0 guide.
• Pin the local Flutter SDK to 3.47.1 via .fvmrc (FVM cache remains gitignored).

pin_code_fields_liquid_glass and showcase are not migrated here and can stay on 9.x / SDK Material until a follow-up.

Test plan

• flutter test in packages/pin_code_fields (all tests passed)
• flutter analyze in packages/pin_code_fields (no issues)
• flutter analyze in packages/pin_code_fields/example (no issues)