fix login, unify backend and frontend in 1 vercel project (#180)

.github/CONTRIBUTING.md

@@ -5,7 +5,6 @@
 To set up the project GitHub-Stats-Extended locally, run the following commands:
 
 ```bash
-./vercel-preparation.sh
 pnpm install
 pnpm run build:packages
 pnpm run dev:frontend

.github/workflows/ci.yml

@@ -33,11 +33,6 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
-      - name: Run vercel-preparation.sh
-        run: |
-          chmod +x ./vercel-preparation.sh
-          ./vercel-preparation.sh
-
       - name: Install Dependencies
         uses: ./.github/actions/install-dependencies
         with: