Hangman mobile

[Ayush3941]

Title: Add Kivy-based Hangman game

Description:

• Ported the existing Tkinter Hangman game to Kivy for cross-platform support (desktop & mobile).
• Preserves all core features: difficulty levels, word display, hangman drawing, on-screen keyboard, hints, and persistent stats.
• Includes polished UI with responsive layout and dynamic hangman drawing.
• Ready for further enhancements like animations, confetti celebration, and improved difficulty controls.

Changes:

• Added HangmanApp.py (Kivy version)
• Reorganized game logic to separate UI (HangmanAppUI) from core game (HangmanGame)
• Maintains fallback word list & persistence (hangman_save.json)

Next steps:

• Integrate micro-animations and hint/celebration effects similar to the Tkinter version.
• Optionally, allow users to select difficulty from UI.