feat: add CI/CD pipeline for Kolo Soroban smart contract

.github/workflows/ci.yml

@@ -0,0 +1,105 @@
+name: Kolo Backend CI
+
+on:
+  push:
+    branches: [ "main", "develop" ]
+  pull_request:
+    branches: [ "main", "develop" ]
+
+env:
+  CARGO_TERM_COLOR: always
+  WORKING_DIR: contracts
+
+jobs:
+  build-and-test:
+    name: Build & Test
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ${{ env.WORKING_DIR }}
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt, clippy
+          targets: wasm32-unknown-unknown
+
+      - name: Cache Cargo dependencies
+        uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: ${{ env.WORKING_DIR }}
+
+      - name: Check formatting
+        run: cargo fmt --all -- --check
+
+      - name: Lint with Clippy
+        run: cargo clippy --all-targets --all-features -- -D warnings
+
+      - name: Build (native)
+        run: cargo build
+
+      - name: Run tests
+        run: cargo test --verbose
+
+      - name: Build WebAssembly (release)
+        run: cargo build --target wasm32-unknown-unknown --release
+
+      - name: Upload WASM artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: kolo-savings-group-wasm
+          path: ${{ env.WORKING_DIR }}/target/wasm32-unknown-unknown/release/kolo_savings_group.wasm
+          retention-days: 14
+
+  deploy:
+    name: Deploy to Testnet
+    runs-on: ubuntu-latest
+    needs: build-and-test
+    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
+    defaults:
+      run:
+        working-directory: ${{ env.WORKING_DIR }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+
+      - name: Cache Cargo dependencies
+        uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: ${{ env.WORKING_DIR }}
+
+      - name: Install Stellar CLI
+        run: |
+          mkdir -p "$HOME/.local/bin"
+          curl -sSL https://github.com/stellar/soroban-tools/releases/download/v21.2.0/soroban-cli-21.2.0-x86_64-unknown-linux-gnu.tar.gz | tar -xz
+          mv soroban "$HOME/.local/bin/soroban"
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+          soroban --version
+
+      - name: Build and optimize WASM
+        run: |
+          RUSTFLAGS="-C target-cpu=mvp" cargo build \
+            --target wasm32-unknown-unknown \
+            --release
+          cargo install wasm-opt --locked
+          wasm-opt \
+            target/wasm32-unknown-unknown/release/kolo_savings_group.wasm \
+            -o target/wasm32-unknown-unknown/release/kolo_savings_group.optimized.wasm
+
+      - name: Deploy contract to testnet
+        env:
+          STELLAR_SOURCE_ACCOUNT: ${{ secrets.STELLAR_DEPLOYER_KEY }}
+        run: |
+          soroban contract deploy \
+            --wasm target/wasm32-unknown-unknown/release/kolo_savings_group.optimized.wasm \
+            --source-account "$STELLAR_SOURCE_ACCOUNT" \
+            --network testnet