web: add /kripke

apps/web/src/lib/components/katex.svelte

@@ -0,0 +1,20 @@
+<script lang="ts">
+import katex from "katex";
+import "katex/dist/katex.min.css";
+import type { HTMLAttributes } from "svelte/elements";
+
+export interface KatexProps extends HTMLAttributes<HTMLDivElement> {
+  displayMode?: boolean;
+  math: string;
+}
+
+let { displayMode, math, ...rest }: KatexProps = $props();
+
+let katexString = $derived.by(() =>
+  katex.renderToString(math, { displayMode, throwOnError: false }),
+);
+</script>
+
+<div {...rest}>
+  {@html katexString}
+</div>