Offline / Low-Bandwidth Mode

[ankit2101]

Summary

Cache the question set and past feedback for a chapter locally in the browser (IndexedDB). Allow students to review cached content without a network connection.

Why

India's internet penetration is ~50% and school connectivity is unreliable in Tier 2/3 cities. The app currently fails entirely without connectivity. Even a read-only offline mode for reviewing cached content dramatically improves utility.

Implementation Notes

• Use Service Workers + IndexedDB via Workbox
• Cache: question sets, feedback, chapter list, student profile
• Offline banner shown when connectivity is lost
• Answer submission queued and sent when connectivity resumes
• Requires HTTPS (already in place)

Acceptance Criteria

• Student can browse their chapter list while offline
• Cached question sets are accessible offline
• Past feedback visible offline
• Answers queued offline and submitted when connectivity returns
• Offline status banner shown clearly