fix: remove kubectl installation, assume available in runner

OPTIMIZATIONS:
- Remove curl-based kubectl installation (inefficient)
- Assume kubectl is available in Gitea runner environment
- Replace port-forward with kubectl exec for test execution
- Tests now run directly inside test pod (not from runner)
- Simpler, faster, more reliable

CI Flow:
  1. go vet + go test (unit tests)
  2. Build image: api-gateway:<sha>
  3. Push: <sha> tag only
  4. Deploy test pod with proper labels
  5. kubectl exec into pod to run tests
  6. Tests run inside pod, can reach services via network policy
  7. Promote to latest only if tests pass
  8. Cleanup test pod

.gitea/workflows/ci.yaml

@@ -70,11 +70,9 @@ jobs:
           KUBECONFIG_B64: ${{ secrets.KUBECONFIG_B64 }}
         continue-on-error: true
 
-      - name: Install kubectl
+      - name: Verify kubectl availability
         run: |
-          curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
-          chmod +x kubectl
-          sudo mv kubectl /usr/local/bin/
+          kubectl version --client || (echo "ERROR: kubectl not available" && exit 1)
 
       - name: Deploy test pod from new image
         run: |
@@ -91,20 +89,16 @@ jobs:
           kubectl wait --for=condition=ready pod -l run=api-gateway-test-${{ steps.sha.outputs.short_sha }} -n api --timeout=60s
         continue-on-error: true
 
-      - name: Run integration tests against test pod
+      - name: Run integration tests inside test pod
         run: |
-          echo "Running integration tests against test pod..."
-          # Port-forward to test pod
-          kubectl port-forward -n api pod/api-gateway-test-${{ steps.sha.outputs.short_sha }} 8080:8080 &
-          PF_PID=$!
-          sleep 3
+          echo "Running integration tests inside test pod..."
+          echo "Test pod: api-gateway-test-${{ steps.sha.outputs.short_sha }}"
+          sleep 5
           
-          # Run tests
-          TEST_RESULT=0
-          go test -v -tags=integration -timeout=5m ./internal/integration/... || TEST_RESULT=$?
-          
-          kill $PF_PID || true
-          exit $TEST_RESULT
+          # Run tests from inside the pod
+          # Pod has network access to all services via network policy labels
+          kubectl exec -n api pod/api-gateway-test-${{ steps.sha.outputs.short_sha }} -- \
+            go test -v -tags=integration -timeout=5m ./internal/integration/...
         env:
           GATEWAY_URL: http://localhost:8080
         continue-on-error: false