added readme

math-tutor/README.md

+## Run the app
+
+Backend (Python):
+```powershell
+cd math-tutor/backend
+python -m venv .venv
+.\.venv\Scripts\Activate.ps1
+pip install -r requirements.txt
+python -m uvicorn app.main:app --reload
+```
+
+Frontend (Vite):
+```powershell
+cd math-tutor/frontend
+npm install
+npm run dev
+```