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/devcontainer.json

@@ -1,22 +1,13 @@
 {
-    "workspaceFolder": "/workspace",
-    "workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind,Z",
-    "runArgs": [
-        "--network=dev-network"
-    ],
-    "build": {
-        "dockerfile": "Dockerfile"
-    },
-    "customizations": {
-        "vscode": {
-            "extensions": [
-                "oven.bun-vscode",
-                "biomejs.biome",
-                "astro-build.astro-vscode"
-            ]
-        }
-    },
-    "forwardPorts": [
-        8080
-    ]
-}
+	"workspaceFolder": "/workspace",
+	"workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind,Z",
+	"runArgs": ["--network=dev-network"],
+	"build": {
+		"dockerfile": "Dockerfile"
+	},
+	"customizations": {
+		"vscode": {
+			"extensions": ["astro-build.astro-vscode", "oxc.oxc-vscode", "esbenp.prettier-vscode"]
+		}
+	}
+}