chore: simplify CI by removing backend and contract jobs

Author: Your Name

.github/workflows/ci.yml

@@ -6,26 +6,6 @@ on:
   pull_request:
     branches: [main, master]
 
-jobs:
-  backend:
-    name: Backend CI
-    runs-on: ubuntu-latest
-    defaults:
-      run:
-        working-directory: backend
-    steps:
-      - uses: actions/checkout@v4
-      - name: Use Node.js
-        uses: actions/setup-node@v4
-        with:
-          node-version: '20'
-          cache: 'npm'
-          cache-dependency-path: backend/package-lock.json
-      - run: npm install
-      - run: npx prisma generate
-      - run: npm run build
-      - run: npm test
-
   frontend:
     name: Frontend CI
     runs-on: ubuntu-latest
@@ -43,18 +23,3 @@ jobs:
       - run: npm install
       - run: npm run build
       - run: npm run lint
-
-  contracts:
-    name: Contracts CI
-    runs-on: ubuntu-latest
-    defaults:
-      run:
-        working-directory: contracts
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
-        with:
-          targets: wasm32-unknown-unknown
-      - run: cargo update -p soroban-sdk
-      - run: cargo build --target wasm32-unknown-unknown