BottomSheet: first attempt for animation

src/timelines/TootThread.tsx

@@ -1,5 +1,5 @@
 import type { mastodon } from "masto";
-import { Show, createResource, createSignal, type Component } from "solid-js";
+import { Show, createResource, createSignal, type Component, type Ref } from "solid-js";
 import CompactToot from "./CompactToot";
 import { useTimeSource } from "../platform/timesrc";
 import RegularToot from "./RegularToot";
@@ -7,6 +7,7 @@ import cardStyle from "../material/cards.module.css";
 import { css } from "solid-styled";
 
 type TootThreadProps = {
+  ref?: Ref<HTMLElement>,
   status: mastodon.v1.Status;
   client: mastodon.rest.Client;
   expanded?: 0 | 1 | 2;
@@ -70,6 +71,7 @@ const TootThread: Component<TootThreadProps> = (props) => {
 
   return (
     <article
+      ref={props.ref}
       classList={{ "thread-line": !!inReplyTo(), expanded: expanded() > 0 }}
       onClick={() => props.onExpandChange?.(nextExpandLevel[expanded()])}
     >