Added full support of clean pomodoro timer implementation

[inderjeet20]

Fixes #760

Description

This PR introduces a fully functional, persistent Pomodoro Timer to enhance productivity, integrated seamlessly alongside the existing standard Timer tab. The design focuses on a highly minimalist, distraction-free user experience while maintaining robust background persistence.

Key Features

• Full Pomodoro Lifecycle: Built-in support for Work phases, Short Breaks, and customizable Session tracking.
• Modern & Minimalist UI:
  • Clean, oversized timer display.
  • Setup duration pickers are tucked away in a sleek BottomSheet to reduce visual clutter.
  • Modern, floating circular action buttons for Play/Pause, Skip, and Reset.
• State Persistence: Integrated with get_storage. The active Pomodoro phase, elapsed time, and session count survive app restarts and backgrounding perfectly.
• Native Audio Integration: Hooks directly into the application's existing AudioUtils to automatically play completion ringtones when a phase finishes.
• Localization Ready: All new strings use .tr for full i18n support matching the rest of the application.

Technical Details

• Added PomodoroController to manage the complex phase-switching logic and timer ticks.
• Added PomodoroStateModel and extended GetStorageProvider to serialize and restore timer configurations and timestamps.
• Built PomodoroTabView tailored to match the app's primary UI and theme controllers.
• Ensured clean code formatting and 100% compliance with flutter analyze.

Screenshots / Screen Recording

pomo.mp4