Giscus (#209)

* Test giscus on homepage

* Use @giscus/react and support light theme

* Track prefers color scheme

* Create a discussion tab for each version

src/app/hooks/useMediaQuery.ts

@@ -0,0 +1,19 @@
+import { useEffect, useState } from 'preact/hooks'
+
+export function useMediaQuery(query: string): boolean {
+	const [prefers, setPrefers] = useState(matchMedia(query).matches)
+
+	const onChange = (e: MediaQueryListEvent) => {
+		setPrefers(e.matches)
+	}
+
+	useEffect(() => {
+		const mediaQuery = matchMedia(query)
+		mediaQuery.addEventListener('change', onChange)
+		return () => {
+			mediaQuery.removeEventListener('change', onChange)
+		}
+	}, [query])
+
+	return prefers
+}