[BUG] CORS errors on Firefox browser

[clencyc]

Problem

The application works in Chrome but gives CORS errors in Firefox.

Steps to Reproduce

1. Open app in Firefox
2. Try to upload video or analyze
3. See CORS error in console

Error Message

Access to XMLHttpRequest at 'http://localhost:5000/api/analyze-video' 
from origin 'http://localhost:5173' has been blocked by CORS policy

Expected Behavior

Works the same in Firefox as Chrome

Current Behavior

Video upload and analysis endpoints blocked by CORS

Environment

• Firefox 125.x
• Backend: localhost:5000
• Frontend: localhost:5173

Files to Check

• LiveEditBackend/app.py - CORS configuration
• Check: Flask-CORS headers and configuration

Possible Cause

CORS configuration might be too strict or Firefox handling preflight differently

Acceptance Criteria

• Works in Firefox
• Works in Safari
• Works in Edge
• No console warnings
• Security not compromised

Difficulty: Easy-Medium

Estimated time: 1-2 hours