Feat/onboarding tooltip tour

[MARYAMAHMED08]

Related Issue

Closes #359

Summary

Added a step-by-step onboarding tooltip tour for first-time users. .The tour highlights key features of the app with small popups at specific positions, showing users how to use StudyPlan effectively..

Changes Made

• Created js/tour.js with full tour logic.
• Added tour CSS styles to css/index.css matching the existing design system.
• Imported and initialized tour in js/app.js
• Used custom event to trigger tour immediately after login
• Tour is per-user using localStorage with email-based key

Testing

• Tested tour appears immediately after first login
• Tested tour does not appear on subsequent logins
• Tested Skip Tour button ends tour correctly
• Tested Next button progresses through all 5 steps
• Tested with multiple user accounts - each user gets their own tour

Screen recording

StudyPlan.-.Google.Chrome.2026-05-26.05-26-06.mp4

Checklist

• Code follows project style
• Tested locally
• No unrelated changes included
• Documentation updated (if applicable)