feat: Show hidden directories in browser (#1288)

## Summary

* **What is the goal of this PR?** Add setting to display hidden files /
directories in filebrowser / web file browser
* **What changes are included?**

## Additional Context

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### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**< NO >**_

src/network/CrossPointWebServer.cpp

@@ -354,7 +354,7 @@ void CrossPointWebServer::scanFiles(const char* path, const std::function<void(F
     auto fileName = String(name);
 
     // Skip hidden items (starting with ".")
-    bool shouldHide = fileName.startsWith(".");
+    bool shouldHide = !SETTINGS.showHiddenFiles && fileName.startsWith(".");
 
     // Check against explicitly hidden items list
     if (!shouldHide) {