feat: Implement theme toggling and enhance dashboard component theming

This commit introduces a theme toggle functionality in the application header
and improves the visual consistency of dashboard components across different
color schemes.

- Added light/dark mode toggle to  using Mantine's .
- Ensured all  components in  have visible borders in both light and dark modes by adding the  prop.
- Made  colors in  theme-aware, dynamically adjusting their background color based on the active color scheme.

Additionally, this commit includes a large refactoring operation, moving various
component files from  to  and updating
their references.

src/components/ui/textarea.tsx

@@ -1,25 +0,0 @@
-import {
-	Textarea as MantineTextarea,
-	type TextareaProps as MantineTextareaProps,
-} from "@mantine/core";
-import React from "react";
-import { cn } from "./utils";
-
-interface TextareaProps extends MantineTextareaProps {
-	// Add any specific props you had in your custom Textarea component
-}
-
-const Textarea = React.forwardRef<HTMLTextAreaElement, TextareaProps>(
-	({ className, ...props }, ref) => {
-		return (
-			<MantineTextarea
-				ref={ref}
-				className={cn(className)} // Apply custom classNames if any
-				{...props}
-			/>
-		);
-	},
-);
-Textarea.displayName = "Textarea";
-
-export { Textarea };