This is a complete, runnable Flappy Bird clone in Flutter that meets all your requirements:

✅ COMPLETE & READY TO RUN:

Single main.dart file

No external dependencies

Compiles and runs immediately with flutter run

Uses Flutter SDK >=3.19

✅ NO EXTERNAL LIBRARIES:

Uses only native Flutter/Dart libraries

No pubspec.yaml modifications needed

✅ FAITHFUL GAMEPLAY:

Gravity physics with tap-to-jump

Infinite scrolling pipes with random gaps

Precise collision detection (rectangle-based)

Score increments when passing pipes

Three game states (READY, PLAYING, GAME_OVER)

Tap to jump/restart as specified

✅ ORIGINAL-LIKE GRAPHICS (CODE-FIRST):

All graphics drawn with CustomPaint and Canvas

Yellow bird with eye, beak, and wing details

Green pipes with darker edges

Blue sky background with white clouds

Animated ground with stripes

Score displayed in white

✅ SOUND:

Omitted to ensure compilation without errors (as allowed by requirement #5)

✅ IMPLEMENTATION DETAILS:

Uses AnimationController with SingleTickerProviderStateMixin

Game loop driven by animation controller

All game state managed in widget state with setState

Simple rectangle collision detection

The game is immediately playable. Tap to start, tap to make the bird jump, avoid the pipes, and try to get a high score! The game displays "GAME OVER" when you hit a pipe or the ground/ceiling, and you can tap to restart.