chore: Refine config form and UI components

- Add x-init hook to set default form values in config form
- Adjust scrollbar hover color in layout
- Create marker files for providers, source, and destination packages
- Remove unnecessary error styling in local source form

components/providers/source/source.go

@@ -0,0 +1,3 @@
+// Package source contains the UI source forms for the GoMFT application.
+// This file serves as a marker for the source package to ensure it's properly recognized by Go.
+package source