Add pomodoro timer

[Sridattasai18]

Description: Add Pomodoro Timer - A CLI productivity timer that follows the Pomodoro
Technique with customizable work/break durations and session counts.

• Not applicable ← tick this (no issue number)

Type of change:

• New project insert

Project:

• Your Project Name: Pomodoro Timer
• Short Description: A command-line Pomodoro timer with customizable work/break
  sessions. Supports 25/5/15 min defaults and Ctrl+C to stop gracefully.

Checklist — tick ALL of these:

• 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.