docs: fix Mustache template rendering in client-side adoption guide

- Wrapped `api_wrapper.mustache` block with `{% raw %} ... {% endraw %}`
  to prevent Jekyll/Liquid from breaking the template syntax on GitHub Pages.
- Ensured README formatting stays intact in repository view.

Author: barissayli

docs/adoption/client-side-adoption.md

@@ -100,6 +100,8 @@ src/main/resources/openapi-templates/
 
 **`api_wrapper.mustache`**
 
+{% raw %}
+
 ```mustache
 import {{commonPackage}}.ServiceClientResponse;
 
@@ -111,6 +113,8 @@ public class {{classname}}
 }
 ```
 
+{% endraw %}
+
 **`model.mustache`** (partial overlay to delegate wrapper classes to `api_wrapper.mustache`).
 
 These ensure generated wrappers extend the generic base instead of duplicating fields.