Add replies and emoji reactions to chat messages

Every message has a row under it to reply or react. Replying quotes the
message above the composer, and the sent message stores
reply_to_message_id (a plain id, not a foreign key, so deleting the
quoted message only drops the quote). send-message accepts a quote from
any session of the same conversation, so a rollover or a thread that
moved on still sends; the conversation drops a picked quote when its
session changes. The bot reads the quote as "[Replying to ...]" before
the user's turn, file-only replies included, and relayed messages carry
it too.

Reactions are a fixed set (BotMessageReactions) in
bot_message_reactions, one per message, emoji and user or bot. Users
toggle their own through api/admin/bots/react-message, and every bot
gets react_to_message for the session it answers (the user's latest
message by default). Both push the fresh list as server:bot-reaction,
with mine worked out for the session's user.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/pages/admin/bots/[bot_id]/(partials)/user-message-group.tsx

@@ -1,17 +1,23 @@
 import Stack from "@moduletrace/twui/layout/Stack";
+import type { BotWithLastMessage } from "@/src/types";
 import type { MessageGroup } from "../(utils)/group-messages";
 import UserMessage from "./user-message";
 import GroupTimestamp from "./group-timestamp";
 
+type Props = {
+    bot: BotWithLastMessage;
+    group: MessageGroup;
+};
+
 /**
  * Right-aligned ink bubbles (each message's files above it), one
  * timestamp under the group.
  */
-export default function UserMessageGroup({ group }: { group: MessageGroup }) {
+export default function UserMessageGroup({ bot, group }: Props) {
     return (
         <Stack className="w-full gap-1! items-end">
             {group.messages.map((message) => (
-                <UserMessage key={message.id} {...message} />
+                <UserMessage key={message.id} message={message} bot_name={bot.name || "the bot"} />
             ))}
             <GroupTimestamp at={group.at} />
         </Stack>