v1.2.1

What's New

Features

• Bulk PDF Upload — Upload multiple chapter PDFs at once with live per-file progress
• Student Login & Progress — Student accounts with session tracking and progress dashboard
• PDF Viewer — In-app PDF viewer on the student side
• Chapter Rename — Admins can rename chapters directly from the dashboard
• AI Model Selection — Admins can switch Claude models from the settings panel (60s cache + instant invalidation)

Improvements

• Hint API moved to /api/student/hint namespace with 30 hints/session rate limit
• Cross-platform pdftotext binary resolution via shutil.which()
• Null-safe chapter fields in student progress (handles deleted chapters gracefully)
• Subject validation on upload; unique chapter name deduplication

Bug Fixes

• Fixed pdftotext path self-reference bug in pdf_service.py
• Fixed module-level imports in admin.py (previously inside function scope)
• Added null guard for questions_json in student sessions