Done adding the pause and resume option

[devikrishna111]

📌 Description

This PR introduces a Pause and Resume functionality to the Typing Speed Test application.

Previously, users could not pause an ongoing test, which forced them to restart if interrupted. This update improves usability by allowing users to pause the timer without losing progress and resume from the exact remaining time.

The feature ensures accurate WPM calculation by excluding paused duration from the final speed computation.

🔗 Related Issue

Closes: #38

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🛠 Changes Made

• Added a Pause/Resume button to the main UI.
• Implemented timer pause logic to stop countdown without resetting time.
• Disabled typing input during pause and re-enabled it on resume.
• Ensured paused duration is excluded from WPM calculation.
• Disabled Pause button when the test finishes.
• Preserved user input and remaining time during pause.

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✅ Checklist

• [✅ ] I have tested my changes
• [✅ ] My code follows project guidelines
• [ ✅] I have linked the related issue