Update samples for Flutter 3.32+ compatibility

Description

This PR updates four sample projects (asset_transformation, analysis_defaults, android_splash_screen, animations) for compatibility with Flutter 3.32+ and Dart 3.8+.

Changes made:

• Update environment constraints from sdk: ^3.7.0-0 to sdk: '>=3.8.0 <4.0.0'
• Update Flutter constraint to >=3.32.0
• Update all dependencies to latest compatible versions
• Fix analysis linter issues across all samples
• Update iOS AppDelegate in animations sample (replace deprecated @UIApplicationMain with @main)
• Enhance analysis_defaults with comprehensive linter examples
• Update gitignore in asset_transformation for Flutter 3.32+ compatibility

Before:

environment:
  sdk: ^3.7.0-0

After:

environment:
  sdk: '>=3.8.0 <4.0.0'
  flutter: '>=3.32.0'

Related Issues

• Addresses Flutter 3.32+ compatibility requirements
• Resolves iOS deprecation warnings for @UIApplicationMain
• Modernizes linting standards across samples

Pre-launch Checklist

• I read the [Flutter Style Guide] recently, and have followed its advice.
• I signed the [CLA].
• I read the [Contributors Guide].
• I have added sample code updates to the [changelog].
• I updated/added relevant documentation (doc comments with ///).

Testing

• All samples build successfully with Flutter 3.32+
• flutter analyze passes for all updated samples
• Example apps run correctly on latest Flutter
• iOS builds work with updated AppDelegate
• Dependencies resolve without conflicts

Samples Updated

asset_transformation

• ✅ Environment updated to Flutter 3.32+ and Dart 3.8+
• ✅ Dependencies updated to latest versions
• ✅ Gitignore updated for Flutter 3.32+ compatibility

analysis_defaults

• ✅ Linter defaults updated with comprehensive examples
• ✅ Environment updated to Flutter 3.32+ and Dart 3.8+
• ✅ Dependencies updated to latest versions

android_splash_screen

• ✅ Environment updated to Flutter 3.32+ and Dart 3.8+
• ✅ Dependencies updated to latest versions
• ✅ Analysis linter issues resolved

animations

• ✅ Environment updated to Flutter 3.32+ and Dart 3.8+
• ✅ Dependencies updated to latest versions
• ✅ Analysis linter issues resolved
• ✅ iOS AppDelegate updated (deprecated @UIApplicationMain → @main)

Copilot summary

This pull request contains updates to dependencies, platform requirements, and project configurations for Flutter and iOS. The most significant changes include updating the Dart and Flutter SDK versions, increasing the minimum iOS deployment target, and adding new configurations to the iOS project files for better compatibility and build management.

Dependency and SDK Updates:

• Updated Dart SDK version to >=3.8.0 <4.0.0 and Flutter SDK version to >=3.32.0 in analysis_defaults/pubspec.yaml and android_splash_screen/pubspec.yaml to align with the latest SDK releases. [1] [2]
• Upgraded flutter_lints dependency from ^5.0.0 to ^6.0.0 in analysis_defaults/pubspec.yaml.

iOS Platform and Configuration Updates:

• Increased the minimum iOS deployment target from 11.0 to 12.0 across multiple files, including AppFrameworkInfo.plist, Podfile, and Runner.xcodeproj. [1] [2] [3] [4] [5]
• Updated Runner.xcodeproj with new build configurations, frameworks, and scripts for CocoaPods integration and build consistency. This includes adding [CP] Check Pods Manifest.lock script phases, new .xcconfig files, and framework references. [1] [2] [3] [4] [5]

Code Quality Improvements:

• Changed a Row widget declaration in main.dart to use final for immutability.
• Replaced double quotes with single quotes for string consistency in main.dart.

Xcode Project Updates:

• Updated LastUpgradeVersion in Runner.xcscheme from 1430 to 1510 and added a custom LLDB initialization file for debugging. [1] [2] [3]