feat(k8s): add defaults/main.yml, meta/main.yml for all 27 roles + 4 helm templates

- Added defaults/main.yml with production-ready values for all 27 Ansible roles
- Added meta/main.yml with role dependencies (DAG: prereq → namespaces → storage → traefik → cert-manager → services)
- Created 4 missing Helm templates: flink-deployment, kafka-cluster, smartapp-web, smartapp-api
- Fixed YAML syntax error in backup/tasks/main.yml (Velero backupStorageLocation)
- Updated README with domain list, dependencies diagram, and corrected Helm chart names
- All 81 YAML files pass validation

helms/roles/namespaces/defaults/main.yml

@@ -0,0 +1,5 @@
+---
+# Role: namespaces
+# Crée les namespaces Kubernetes
+# Les namespaces sont définis dans group_vars (variable: namespaces)
+# Aucune variable custom supplémentaire requise pour ce rôle.

helms/roles/namespaces/meta/main.yml

@@ -0,0 +1,12 @@
+---
+galaxy_info:
+  author: Eric FELIXINE
+  description: Create and manage Kubernetes namespaces for the platform
+  license: MIT
+  min_ansible_version: "2.15"
+  platforms:
+    - name: Kubernetes
+      versions:
+        - "1.28"
+dependencies:
+  - role: prerequisites