Improve RockPaperScissor UX: Added Reset Button

[Naman1005]

Changes Made

• Added a "Reset Score" button to clear scores without restarting the app.
• Improved "End Game" logic to display the final score summary before quitting.
• Fixed the repetitive image loading logic.

Testing

• Verified that clicking "Reset Score" zeroes out both User and Computer scores.
• Verified that "End Game" displays the correct final score popup.

[AnshMNSoni]

Kindly include test validation in the tests/ directory. This is mandatory to maintain code quality and support long-term maintainability of the common codebase.