feat: add Tekton Pipelines for integration testing

Implement Kubernetes-native CI/CD with Tekton Pipelines:

ARCHITECTURE:
- Tekton Task: Runs integration tests in container
- Tekton Pipeline: Orchestrates test execution
- ArgoCD Application: Manages Tekton installation
- CI: Triggers PipelineRun, reads results, promotes image

FLOW:
1. CI builds image:sha
2. CI creates PipelineRun with new image
3. Tekton controller watches PipelineRun
4. Task executes integration tests
5. Results written to PipelineRun status
6. CI reads status, promotes to :latest if pass
7. ArgoCD detects :latest change and deploys

BENEFITS:
✓ Kubernetes-native (CRDs, no external dependencies)
✓ DRY (parameterized Task/Pipeline)
✓ SOLID (single responsibility, clean interfaces)
✓ GitOps (Tekton managed by ArgoCD)
✓ Observable (logs, status, results)
✓ Secure (non-root, resource limits)

FILES:
- k8s/tekton/task-integration-test.yaml: Task definition
- k8s/tekton/pipeline-integration-test.yaml: Pipeline definition
- k8s/tekton/kustomization.yaml: Kustomize management
- k8s/tekton/README.md: Documentation
- k8s/argocd-apps/tekton.yaml: ArgoCD Application
- .gitea/workflows/ci.yaml: Updated CI to use Tekton

NEXT:
1. Merge PR
2. ArgoCD syncs and installs Tekton
3. First git push triggers PipelineRun
4. Integration tests run in cluster
5. Results feedback to CI

.gitea/workflows/ci.yaml

@@ -47,19 +47,15 @@ jobs:
         run: |
           docker build --no-cache \
             -t "${IMAGE}:${{ steps.sha.outputs.short_sha }}" \
-            -t "${IMAGE}:latest" \
             -f Dockerfile .
+          echo "Built image: ${IMAGE}:${{ steps.sha.outputs.short_sha }}"
 
-      - name: Push Docker image
+      - name: Push test image (SHA tag only, not latest yet)
         run: |
           docker push "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
-          docker push "${IMAGE}:latest"
-          echo "✓ Pushed: ${IMAGE}:${{ steps.sha.outputs.short_sha }}"
+          echo "✓ Pushed test image: ${IMAGE}:${{ steps.sha.outputs.short_sha }}"
 
-      - name: Prune unused images
-        run: docker image prune -a --force 2>&1 | tail -3 || true
-
-      - name: Setup kubeconfig
+      - name: Setup kubeconfig for Tekton trigger
         run: |
           mkdir -p ~/.kube
           echo "${KUBECONFIG_B64}" | base64 -d > ~/.kube/config
@@ -67,16 +63,75 @@ jobs:
           KUBECONFIG_B64: ${{ secrets.KUBECONFIG_B64 }}
         continue-on-error: true
 
-      - name: Install kubectl
+      - name: Trigger integration tests via Tekton PipelineRun
         run: |
-          curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
-          chmod +x kubectl
-          sudo mv kubectl /usr/local/bin/
+          echo "Triggering integration tests via Tekton..."
+          
+          # Create PipelineRun to run integration tests
+          kubectl create -f - << 'YAML'
+          apiVersion: tekton.dev/v1
+          kind: PipelineRun
+          metadata:
+            name: integration-test-${{ steps.sha.outputs.short_sha }}
+            namespace: api
+            labels:
+              pr-id: "${{ github.event.pull_request.number || 'main' }}"
+              commit-sha: "${{ steps.sha.outputs.short_sha }}"
+          spec:
+            pipelineRef:
+              name: integration-test-pipeline
+            params:
+            - name: image
+              value: ${IMAGE}:${{ steps.sha.outputs.short_sha }}
+            - name: test-timeout
+              value: "5m"
+          YAML
+          
+          echo "✓ PipelineRun created: integration-test-${{ steps.sha.outputs.short_sha }}"
+          
+          # Wait for PipelineRun completion
+          echo "Waiting for tests to complete (max 10 minutes)..."
+          kubectl wait --for=condition=Succeeded \
+            pipelineruns/integration-test-${{ steps.sha.outputs.short_sha }} \
+            -n api --timeout=10m 2>/dev/null || \
+          kubectl wait --for=condition=Failed \
+            pipelineruns/integration-test-${{ steps.sha.outputs.short_sha }} \
+            -n api --timeout=1s 2>/dev/null || true
+          
+          # Get test results
+          echo ""
+          echo "=== Test Results ==="
+          RESULT=$(kubectl get pipelinerun integration-test-${{ steps.sha.outputs.short_sha }} \
+            -n api -o jsonpath='{.status.conditions[0].reason}')
+          TEST_MESSAGE=$(kubectl get pipelinerun integration-test-${{ steps.sha.outputs.short_sha }} \
+            -n api -o jsonpath='{.status.taskRuns[*].status.taskResults[?(@.name=="result")].value}')
+          
+          echo "PipelineRun Status: $RESULT"
+          echo "Test Result: $TEST_MESSAGE"
+          
+          # Get logs
+          echo ""
+          echo "=== Test Logs ==="
+          kubectl logs -n api pipelinerun/integration-test-${{ steps.sha.outputs.short_sha }} || true
+          
+          # Determine if tests passed
+          if [ "$RESULT" = "Succeeded" ]; then
+            echo "✓ Integration tests PASSED"
+            exit 0
+          else
+            echo "✗ Integration tests FAILED"
+            exit 1
+          fi
+        continue-on-error: false
 
-      - name: Run integration tests against cluster
+      - name: Promote image to latest (only if tests passed)
+        if: success()
         run: |
-          echo "Running integration tests against production cluster..."
-          go test -v -tags=integration ./internal/integration/... || true
-        env:
-          GATEWAY_URL: http://api-gateway.api.svc.cluster.local:8080
-        continue-on-error: true
+          docker pull "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
+          docker tag "${IMAGE}:${{ steps.sha.outputs.short_sha }}" "${IMAGE}:latest"
+          docker push "${IMAGE}:latest"
+          echo "✓ Promoted ${IMAGE}:${{ steps.sha.outputs.short_sha }} to latest"
+
+      - name: Cleanup
+        if: always()
+        run: docker image prune -a --force 2>&1 | tail -3 || true