Cleanup: Remove dead Flask/flask-cors dependencies and delete deprecated db.py

[anushagarg6]

Description

Two cleanup tasks remain from the Flask → FastAPI migration:

1. Dead dependencies in requirements.txt

flask==3.0.3 and flask-cors==4.0.1 are still listed even though the app fully runs on FastAPI. These are never imported anywhere in the current codebase and add unnecessary bloat (~15MB) to every fresh install.

2. Deprecated backend/db.py still exists

The file itself says at the top:

"""db.py — DEPRECATED
Delete it once you've confirmed nothing imports from here directly."""

Nothing in the current codebase imports from db.py. It is safe to delete.

Fix Needed

1. Remove flask==3.0.3 and flask-cors==4.0.1 from requirements.txt
2. Delete backend/db.py

Files Affected

• requirements.txt
• backend/db.py