fix: Define stacks_base_path variable with default value

- Add stacks_base_path variable with default '/home/deploy'
- Fixes 'stacks_base_path is undefined' error in install-composer-dependencies playbook

deployment/ansible/playbooks/install-composer-dependencies.yml

@@ -5,6 +5,8 @@
   become: no
 
   vars:
+    # Base path for deployment stacks
+    stacks_base_path: "{{ stacks_base_path | default('/home/deploy') }}"
     # Determine stack path based on environment
     application_stack_dest: >-
       {%- if deployment_environment == 'staging' -%}