Fix/Color Game missing icon crash, path resolution, scoring logic, and README (#472)

[Prayas340]

Description

Fixes #472

This PR fixes several bugs and improves the user experience and documentation in \Color_Game:

• Resolves startup crash when \color_game_icon.ico\ is missing by adding existence checks and safe error handling.

• Fixes relative file path resolution for \highest_score.txt\ using _file_-relative directory resolution.

• Resolves the initial keypress evaluation bug where unprompted input was scored on game start.

• Replaces secondary \ k.Tk()\ root instance in \scoreshow()\ with \messagebox.showinfo\ to avoid duplicate Tcl interpreter roots.

• Adds an in-game restart button and replay flow so players can restart without relaunching the script.

• Updates and expands \README.md\ following repository documentation guidelines.

• Issue_no: [Color_Game] Fix missing icon crash, relative file path resolution, scoring logic, and add game restart #472

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation Update

Project

• Your Project Name: Color Game

• Short Description: Python Tkinter GUI game testing cognitive speed via the Stroop Effect with real-time scoring, countdown timer, and high score tracking.

Checklist:

• I have named my files and folder, according to this project's guidelines.
• My code follows the style guidelines of this project.
• I have commented on my code, particularly in hard-to-understand areas.
• I have created a helpful and easy to understand \README.md.
• My changes do not produce any warnings.