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/index.tsx

@@ -0,0 +1,23 @@
+import React from "react";
+import Row from "@moduletrace/twui/layout/Row";
+import BotsRail from "./(sections)/bots-rail";
+
+/**
+ * Full-bleed chat shell for `/admin/bots/*`: the rail of bot conversations,
+ * then the page (conversation + working-on panel). No cards, no shadows;
+ * regions are separated by 1px hairlines.
+ */
+export default function BotsLayout({
+    children,
+}: {
+    children: React.ReactNode;
+}) {
+    return (
+        <Row className="w-full h-screen gap-0! flex-nowrap items-stretch overflow-hidden bg-paper text-ink">
+            <BotsRail />
+            <Row className="grow min-w-[480px] h-full gap-0! flex-nowrap items-stretch">
+                {children}
+            </Row>
+        </Row>
+    );
+}