Add time-tracking feature (#2890)

[anshul23102]

Summary

Implements comprehensive time-tracking functionality for devtrack, resolving issue #2890. Users can now create tasks, start/stop timers with real-time elapsed display, view session history, and see aggregated time logged over the past 7 days via a dashboard chart widget.

Changes

• Database: Supabase migration adding tasks and time_entries tables with proper foreign key constraints and indexes for efficient user_id and date-based queries.
• API Routes: Five new Next.js API routes handling task CRUD, time entry creation with server-side duration calculation, and daily summary aggregation. All endpoints include authentication via NextAuth and authorization checks to prevent cross-user data access.
• Frontend Components:
  • TaskTimeTracker.tsx: Full-featured timer component with start/stop controls, session history, localStorage-based persistence across page refreshes, and per-task deletion.
  • DailyTimeWidget.tsx: Dashboard widget displaying 7-day bar chart of logged minutes with error states and empty state handling.
• Dashboard Integration: Added new widget types to the dashboard registry and integrated both components into the goals section with responsive layout.

Implementation Details

• Timer state persists via localStorage using ISO 8601 timestamps, automatically resuming on page refresh.
• Duration always calculated server-side from start/end timestamps to prevent client-side manipulation.
• All API endpoints enforce user-based authorization to ensure users can only access/modify their own data.
• Responsive design follows devtrack's existing CSS variable system.

Closes #2890

[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[anshul23102]

Hey, requesting a review for this time-tracking feature implementation. The code covers database schema, API endpoints with proper authentication/authorization checks, and full frontend components with localStorage persistence.

CI checks are in progress. Let me know if you have any feedback on the approach or implementation details.

Some potentially relevant labels for tracking: enhancement, type:feature (given the new feature scope)