Fix broken documentation links after file reorganization

- Fix links in docs/guides/advanced/README.md to point to core-concepts/
- Fix asset link in docs/upgrading/release-notes/16.0.0.md
- Fix turbolinks link in docs/upgrading/release-notes/16.0.0.md

All broken links reported by markdown-link-check CI have been fixed.

Author: justin808

docs/guides/advanced/README.md

@@ -2,6 +2,6 @@
 
 Advanced React on Rails features and patterns.
 
-- [Auto-Bundling](../auto-bundling-file-system-based-automated-bundle-generation.md)
-- [Server-Side Rendering](../react-server-rendering.md)
-- [Performance Optimization](../webpack-configuration.md)
+- [Auto-Bundling](../../core-concepts/auto-bundling-file-system-based-automated-bundle-generation.md)
+- [Server-Side Rendering](../../core-concepts/react-server-rendering.md)
+- [Performance Optimization](../../core-concepts/webpack-configuration.md)

docs/upgrading/release-notes/16.0.0.md

@@ -34,7 +34,7 @@ This optimization is particularly impactful for:
 
 _Performance improvement visualization:_
 
-![Performance comparison showing early hydration improvement](../assets/early-hydration-performance-comparison.jpg)
+![Performance comparison showing early hydration improvement](../../assets/early-hydration-performance-comparison.jpg)
 
 _The image above demonstrates the dramatic performance improvement:_
 
@@ -81,7 +81,7 @@ _The image above demonstrates the dramatic performance improvement:_
     // Code expecting all components to be hydrated
     ```
 
-  - If you call it in a `turbolinks:load` listener to work around the issue documented in [Turbolinks](../building-features/turbolinks.md#async-script-loading), the listener can be safely removed.
+  - If you call it in a `turbolinks:load` listener to work around the issue documented in [Turbolinks](../../building-features/turbolinks.md#async-script-loading), the listener can be safely removed.
 
 ### Script Loading Strategy Migration