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.

.oxlintrc.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "plugins": ["unicorn", "typescript", "oxc"],
+  "categories": {
+    "correctness": "error",
+    "perf": "error",
+    "suspicious": "off",
+    "style": "off",
+    "nursery": "off",
+    "pedantic": "off",
+    "restriction": "off"
+  },
+  "ignorePatterns": ["node_modules/", ".astro/", "dist/"]
+}