Fix React & Python Performance

My web app runs a React front end on top of a Python back end, and the whole thing has slowed to a crawl. The interface often stops responding, so the core of this job is to remove every performance bottleneck on both sides of the stack.

I need you to profile the React code, trace what is blocking the main thread, streamline state management, and optimise the bundle. At the same time, audit the Python endpoints for slow queries or blocking calls that could be starving the UI of data. Once you have solid numbers on where the lag originates, apply the fixes, refactor where it makes sense, and push the changes to the Git repository on a dedicated branch.

You will have Docker-based local setup instructions, existing automated tests, and direct access to me for quick feedback.

Deliverables
• A responsive UI with no noticeable input lag under typical load
• Back-end endpoints that return within acceptable latency thresholds
• A short before/after report summarising the changes and measured gains

If you are comfortable jumping between React debugging tools and Python profilers, this should be a straightforward but rewarding task.