Build Cobble project structure from the handoff

- Remove the preset document suite (letters, emails, invoices, quotes,
  PDF generation, line items) with its routes, API handlers and tables
- Rebrand to Cobble: site data, Lato, handoff design tokens (light and
  dark) in main.css, brand assets in public/brand, ember stone logo and
  regenerated favicons
- Add bots, bot_messages, bot_tasks and bot_task_steps tables, regenerate
  DB types (BUN_SQLITE_COBBLE_*) and add a sample crew seed (seed:bots)
- Add the chat shell at /admin/bots: rail with pinned coordinator and
  user popover, bottom-anchored conversation with composer, working-on
  panel, and a send-message API scoped to the session user
- Add BotStone and Wordmark components, crew status and relative time
  utils with tests, and update AGENTS.md

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

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

@@ -0,0 +1,33 @@
+import Stack from "@moduletrace/twui/layout/Stack";
+import type { BUN_SQLITE_COBBLE_BOT_MESSAGES } from "@/db/types/db";
+import type { BotWithLastMessage } from "@/src/types";
+import groupMessages from "../(utils)/group-messages";
+import MessageGroupBlock from "./message-group-block";
+
+type Props = {
+    bot: BotWithLastMessage;
+    messages: BUN_SQLITE_COBBLE_BOT_MESSAGES[];
+};
+
+/**
+ * Bottom-anchored: the stack sits 24px above the composer rule and grows
+ * upward. Empty space belongs at the top. New messages announce politely.
+ */
+export default function MessageThread({ bot, messages }: Props) {
+    const groups = groupMessages({ messages });
+
+    return (
+        <Stack className="grow min-h-0 gap-0! items-stretch overflow-y-auto flex-col-reverse">
+            <Stack
+                role="log"
+                aria-live="polite"
+                aria-label={`Conversation with ${bot.name}`}
+                className="w-full gap-4! items-stretch px-6 pt-6 pb-6"
+            >
+                {groups.map((group) => (
+                    <MessageGroupBlock key={group.key} bot={bot} group={group} />
+                ))}
+            </Stack>
+        </Stack>
+    );
+}