Implement Time Tracking Integration

[ExPl0iT-29]

Description: Add Pomodoro-style time tracking to tasks
Acceptance Criteria:

New command: tasktrek start <task_id>

Live timer display with elapsed time

Automatic time logging to tasks

Weekly time reports
Files Affected:

tasktrek

tasktrek-lib.sh

New time-tracking.sh module
Suggested Approach:
Background process for timers. Store time data in separate JSON file
Difficulty Level: ⭐️⭐️⭐️⭐️ (4/5)