fix: remove redundant shadcn component className overrides

src/app/auth/signin/page.tsx

@@ -55,13 +55,8 @@ export default function SignInPage() {
 					Sign in to unlock AI-powered event creation
 				</p>
 
-				<Button
-					onClick={handleSignIn}
-					className="w-full"
-					size="default"
-					disabled={isLoading}
-				>
-					{isLoading ? <Loader2 className="h-4 w-4 animate-spin mr-2" /> : null}
+				<Button onClick={handleSignIn} className="w-full" disabled={isLoading}>
+					{isLoading ? <Loader2 className="h-4 w-4 animate-spin" /> : null}
 					{isLoading ? "Signing in..." : "Continue with Authentik"}
 				</Button>