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/layouts/bots/(partials)/rail-user-menu.tsx

@@ -0,0 +1,27 @@
+import Paper from "@moduletrace/twui/elements/Paper";
+import Divider from "@moduletrace/twui/layout/Divider";
+import { RailUserMenuItems } from "../(dict)/rail-user-menu-dict";
+import RailUserMenuEntry from "./rail-user-menu-entry";
+
+/**
+ * 220px popover: the only element in the shell with elevation.
+ */
+export default function RailUserMenu() {
+    const items = RailUserMenuItems.filter((item) => !item.destructive);
+    const destructive = RailUserMenuItems.filter((item) => item.destructive);
+
+    return (
+        <Paper
+            role="menu"
+            className="w-[220px] mb-1 p-0! py-1 gap-0! items-stretch rounded-default bg-surface dark:bg-surface border-hairline dark:border-hairline shadow-popover! dark:shadow-popover!"
+        >
+            {items.map((item) => (
+                <RailUserMenuEntry key={item.title} {...item} />
+            ))}
+            <Divider className="my-1 mx-3 w-auto border-hairline dark:border-hairline" />
+            {destructive.map((item) => (
+                <RailUserMenuEntry key={item.title} {...item} />
+            ))}
+        </Paper>
+    );
+}