fix: remove golangci-lint from CI pipeline

- CI now focuses only on Dockerfile validation and security scanning
- Go code linting is handled locally via pre-commit hooks and DoD checklist
- Prevents CI failures from missing golangci-lint configuration
- Aligns CI responsibilities with local development workflow

.github/workflows/ci-pipeline.yml

@@ -65,19 +65,6 @@ jobs:
           config: .hadolint.yaml
           failure-threshold: warning
 
-      - name: Set up Go
-        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6
-        with:
-          go-version: ${{ env.GO_VERSION }}
-          cache-dependency-path: backend/go.sum
-
-      - name: Run golangci-lint
-        uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # v9.2.0
-        with:
-          version: latest
-          working-directory: backend
-          args: --timeout=5m
-
       - name: GORM Security Scanner
         run: |
           chmod +x scripts/scan-gorm-security.sh