docs(guides): update styling and theming guide links

- Replace outdated link to UI customization guide with the current customization page URL
- Update links in both mobile client and web dashboard styling and theming guides

Author: fulleni

src/content/docs/mobile-client/guides/styling-and-theming.mdx

@@ -11,7 +11,7 @@ Because this is a cross-application concern, the primary, hands-on guide for mak
 <Aside type="tip" title="Start Here for Customization">
 To learn how to properly customize the UI, please follow our comprehensive, step-by-step tutorial:
 
-[**Guide: Customizing the UI Theme &rarr;**](/docs/architecture/03-guide-customizing-the-ui/)
+[**Guide: Customizing the UI Theme &rarr;**](/docs/customization/)
 </Aside>
 
 This approach ensures that you learn the correct workflow for modifying shared code, which is the key to unlocking the full power of the toolkit.

src/content/docs/web-dashboard/guides/styling-and-theming.mdx

@@ -11,7 +11,7 @@ Because this is a cross-application concern, the primary, hands-on guide for mak
 <Aside type="tip" title="Start Here for Customization">
 To learn how to properly customize the UI, please follow our comprehensive, step-by-step tutorial:
 
-[**Guide: Customizing the UI Theme &rarr;**](/docs/architecture/03-guide-customizing-the-ui/)
+[**Guide: Customizing the UI Theme &rarr;**](/docs/customization/)
 </Aside>
 
 This approach ensures that you learn the correct workflow for modifying shared code, which is the key to unlocking the full power of the toolkit.