CHORE: Remove Tekton CI/CD platform

- Delete tekton/ directory (pipeline, triggers, dashboard, ci-cd)
- Remove tekton references from kustomization.yaml
- Switching to GitHub Actions for CI/CD

tekton/triggers/argocd.yaml

@@ -1,40 +0,0 @@
-apiVersion: argoproj.io/v1alpha1
-kind: Application
-metadata:
-  name: tekton-triggers
-  namespace: argocd
-  finalizers:
-  - resources-finalizer.argocd.argoproj.io
-spec:
-  project: default
-  source:
-    repoURL: https://github.com/K3S-HOME/platform.git
-    targetRevision: main
-    path: tekton/triggers
-  destination:
-    server: https://kubernetes.default.svc
-    namespace: tekton-pipelines
-  ignoreDifferences:
-  - group: apiextensions.k8s.io
-    kind: CustomResourceDefinition
-    jsonPointers:
-    - /status
-    - /spec/preserveUnknownFields
-  syncPolicy:
-    automated:
-      prune: true
-      selfHeal: true
-      allowEmpty: false
-    syncOptions:
-    - CreateNamespace=true
-    - PrunePropagationPolicy=foreground
-    - PruneLast=true
-    - RespectIgnoreDifferences=true
-    - Replace=true
-    retry:
-      limit: 5
-      backoff:
-        duration: 5s
-        factor: 2
-        maxDuration: 3m
-  revisionHistoryLimit: 10