Add custom time support to Pomodoro timer

[chn25csd565-bit]

📌 Description

Added custom time input support to the Pomodoro Timer, allowing users to personalize focus and break sessions according to their workflow.

🔗 Related Issue

Closes #1511

🛠 Changes Made

• Added custom duration inputs for Focus, Short Break, and Long Break sessions.
• Added validation to prevent invalid timer values and enforce reasonable limits.
• Added Focus / Short Break / Long Break mode selection.
• Updated timer logic to use user-defined durations while keeping existing timer functionality.
• Improved Pomodoro UI with responsive settings panel and theme-matching styling.

✅ Checklist

• Code runs locally
• Followed project structure
• No console errors
• Properly tested changes
• Linked the issue

🚀 Notes for Reviewers

Please review the custom timer flow, validation limits, and UI responsiveness.

[aryandas2911]

lint pls