Add enterprise appliance experience Phase 1 foundation

ansible/roles/cezen-backend/tasks/main.yml

@@ -43,6 +43,21 @@
     mode: "0640"
   when: cezen_license_file.stat.exists
 
+- name: Check for existing appliance database before schema migration
+  stat:
+    path: /opt/cezen/data/cezen.db
+  register: cezen_existing_db
+
+- name: Create pre-deploy database safety copy
+  copy:
+    src: /opt/cezen/data/cezen.db
+    dest: /opt/cezen/data/cezen.db.pre-deploy
+    remote_src: yes
+    owner: "{{ cezen_user }}"
+    group: "{{ cezen_user }}"
+    mode: "0600"
+  when: cezen_existing_db.stat.exists
+
 - name: Copy FastAPI application
   copy:
     src: main.py