refactor: improve Ansible playbooks and enforce linting standards

- refactor playbooks to follow best practices
- implement Ansible Vault for secrets management
- replace direct service restarts with handlers
- add Molecule testing framework with Docker

lint compliance:
- fix all ansible-lint violations (FQCN, booleans, file modes)
- remove duplicate tasks and improve structure
- enforce consistent task ordering and formatting
- add noqa where necessary for edge cases

documentation:
- add REFACTORING.md and VAULT_GUIDE.md
- improve per-role documentation

all playbooks now pass ansible-lint production profile with 0 violations

.gitea/workflows/ci.yml

@@ -3,29 +3,28 @@ name: ci
 on:
   push:
     branches: [main]
-  pull_request:
-    branches: [main]
 
 jobs:
   validate:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu
+
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install deps
+        run: |
+          apt-get update
+          apt-get install -y python3 python3-pip ansible docker.io
+
       - name: Python syntax check
         run: |
-          python3 -m py_compile \
-            migration-validation-framework/cli.py \
-            migration-validation-framework/collectors/*.py \
-            migration-validation-framework/validators/*.py \
-            migration-validation-framework/reports/*.py
+          find migration-validation-framework -name "*.py" -exec python3 -m py_compile {} \;
 
       - name: Ansible syntax check
         run: |
-          python3 -m pip install --user ansible
           ansible-playbook -i enterprise-infra-simulator/inventory/hosts.ini \
             --syntax-check enterprise-infra-simulator/playbooks/*.yml
 
       - name: Docker compose validation
         run: |
-          docker compose -f observability-stack/docker-compose.yml config
+          docker compose -f observability-stack/docker-compose.yml config