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/button.tsx

@@ -1,60 +0,0 @@
-import {
-	Button as MantineButton,
-	type ButtonProps as MantineButtonProps,
-} from "@mantine/core";
-import { cn } from "./utils";
-
-interface ButtonProps extends MantineButtonProps {
-	variant?:
-		| "default"
-		| "destructive"
-		| "outline"
-		| "secondary"
-		| "ghost"
-		| "link";
-	className?: string;
-	onClick?: React.MouseEventHandler<HTMLButtonElement>;
-	type?: "button" | "submit" | "reset";
-}
-
-const Button = ({ children, className, variant, ...props }: ButtonProps) => {
-	let mantineVariant: MantineButtonProps["variant"];
-	let mantineColor: MantineButtonProps["color"];
-
-	switch (variant) {
-		case "destructive":
-			mantineVariant = "filled";
-			mantineColor = "red";
-			break;
-		case "outline":
-			mantineVariant = "outline";
-			break;
-		case "secondary":
-			mantineVariant = "default";
-			break;
-		case "ghost":
-			mantineVariant = "subtle";
-			break;
-		case "link":
-			mantineVariant = "transparent";
-			mantineColor = "blue"; // Assuming primary maps to blue in Mantine for now
-			break;
-		default:
-			mantineVariant = "filled";
-			mantineColor = "blue"; // Assuming primary maps to blue in Mantine for now
-			break;
-	}
-
-	return (
-		<MantineButton
-			variant={mantineVariant}
-			color={mantineColor}
-			className={cn(className)}
-			{...props}
-		>
-			{children}
-		</MantineButton>
-	);
-};
-
-export { Button };