fix: refine regex to limit snippet insertion to specific Proxmox storage

tasks/preflight-checks.yml

@@ -165,12 +165,8 @@
         regexp: '^(\s*content\s+.*)(?<!snippets)$'
         line: '\1,snippets'
         backrefs: yes
-        # Only apply inside the block for the specified storage
-        # by matching the storage ID and content line together
-        # e.g. "dir: local" followed by "    content ..."
-        # This ensures we don't touch other storages
-        # Use 'search_string' to anchor the block
-        search_string: "dir: {{ proxmox_snippets_storage }}"
+        # Limit the match to lines following the correct storage ID
+        insertafter: "^dir: {{ proxmox_snippets_storage }}$"
         
     - name: "[PREFLIGHT] Ensure snippets storage directory exists"
       ansible.builtin.file: