refactor(description-image-dropzone, app-store): update styling and enhance project history cycling logic

- Changed button styling in the DescriptionImageDropZone component to use primary color classes for better visual consistency.
- Improved project history cycling logic in the app store by filtering out invalid projects, ensuring smoother navigation through valid project history.

These changes enhance the user interface and improve the reliability of project navigation within the application.

app/src/components/ui/description-image-dropzone.tsx

@@ -292,7 +292,7 @@ export function DescriptionImageDropZone({
         <button
           type="button"
           onClick={handleBrowseClick}
-          className="text-blue-500 hover:text-blue-400 underline"
+          className="text-primary hover:text-primary/80 underline"
           disabled={disabled || isProcessing}
         >
           browse