Focus Session Analytics Dashboard

[Aditya8369]

Description
Add detailed analytics for focus sessions including productivity trends, peak hours, break patterns, and session history with visual charts.

Steps to Implement
Add Focus Analytics Types (types.ts):

Add FocusSession interface: id, startTime, endTime, durationMinutes, taskId, taskTitle, completed
Add FocusAnalytics interface: totalSessions, totalFocusTime, averageSessionLength, completionRate, dailyStats
Create Analytics Service (services/focusAnalyticsService.ts):

Add functions: logFocusSession(), getWeeklyStats(), getMonthlyStats(), getProductiveHours()
Create Focus Analytics Component (components/FocusAnalytics.tsx):

Weekly bar chart showing daily focus time
Pie chart for task distribution
Best study hours heatmap
Session history list
Update Focus Page (pages/Focus.tsx):

Add "View Analytics" button
Integrate analytics display

[Aditya8369]

@Antarik06 please assign me