Tekton Phase 2 Day 3: Complete Harbor authentication and test build

- Added config.json key to harbor-credentials ExternalSecret
  This ensures kaniko can find the Docker auth config at /kaniko/.docker/config.json
  (previously only .dockerconfigjson was present)

- Created test-app-build PipelineRun manifest for validation testing

- Successfully validated end-to-end pipeline:
  ✅ git-clone Task deployed and working
  ✅ kaniko-build Task deployed and working
  ✅ container-build Pipeline deployed and working
  ✅ Harbor authentication working with robot account
  ✅ Test image built and pushed: the-seas.local.mk-labs.cloud/library/test-app:v1.0.0
  ✅ Image digest: sha256:aa143f4a01795a1d307b711108ca0c89f36e00ea38fddb9d7b2febd5fffc46d7

Pipeline test results:
- PipelineRun: test-app-build-005 - SUCCEEDED
- fetch-repository TaskRun - SUCCEEDED
- build-and-push TaskRun - SUCCEEDED

Tekton CI/CD platform is now operational and ready for production workloads.

cluster/platform/innoventions/harbor-credentials.yaml

@@ -27,6 +27,16 @@ spec:
               }
             }
           }
+        config.json: |
+          {
+            "auths": {
+              "the-seas.local.mk-labs.cloud": {
+                "username": "{{ .tekton_username }}",
+                "password": "{{ .tekton_password }}",
+                "auth": "{{ printf "%s:%s" .tekton_username .tekton_password | b64enc }}"
+              }
+            }
+          }
   data:
     - secretKey: tekton_username
       remoteRef: