add: user balance

Fix CORS and production URLs

Deploying to Hugging Face

fix: changed to postgresql

add: authorized pages, firebase

add: books, borrowings, home, login, membership, register, reward, userinsights, wishlist, themes

add: blazor web assembly.

add: removed firebase json file

add: change userid to guid and small fixes

add: loyalty reward system

feat: restructure backend project, add configuration files, implement authentication, user and book management, and enhance borrowing and subscription features