Remove obsolete tests and add new login page layout

- Deleted test files for NavLink, Navbar, NavbarBrand, Progress, Row, SearchBar, Select, Spinner, Textarea, and a basic test for Button.
- Introduced a new EmptyLayout component for consistent layout structure.
- Added a new login page with a layout that includes a login form and an ASCII art header.
- Updated CSS variables for improved styling consistency across components.
- Removed Vitest configuration file as it is no longer needed.

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM node:lts
+FROM node:24
 
 WORKDIR /app