refactor(server): auth (#5895)

Remove `next-auth` and implement our own Authorization/Authentication system from scratch.

## Server

- [x] tokens
  - [x] function
  - [x] encryption

- [x] AuthController
  - [x] /api/auth/sign-in
  - [x] /api/auth/sign-out
  - [x] /api/auth/session
  - [x] /api/auth/session (WE SUPPORT MULTI-ACCOUNT!)

- [x] OAuthPlugin
  - [x] OAuthController
  - [x] /oauth/login
  - [x] /oauth/callback
  - [x] Providers
    - [x] Google
    - [x] GitHub

## Client

- [x] useSession
- [x] cloudSignIn
- [x] cloudSignOut

## NOTE:

Tests will be adding in the future

packages/backend/server/src/fundamentals/index.ts

@@ -14,6 +14,7 @@ export {
 } from './config';
 export * from './error';
 export { EventEmitter, type EventPayload, OnEvent } from './event';
+export { CryptoHelper, URLHelper } from './helpers';
 export { MailService } from './mailer';
 export { CallCounter, CallTimer, metrics } from './metrics';
 export {
@@ -21,7 +22,6 @@ export {
   GlobalExceptionFilter,
   OptionalModule,
 } from './nestjs';
-export { SessionService } from './session';
 export * from './storage';
 export { type StorageProvider, StorageProviderFactory } from './storage';
 export { AuthThrottlerGuard, CloudThrottlerGuard, Throttle } from './throttler';