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/index.tsx

@@ -0,0 +1,12 @@
+import type { BunextPageModuleMeta } from "@moduletrace/bunext/types";
+import { SiteData } from "@/src/data/site-data";
+import EmptyCrew from "./(sections)/empty-crew";
+
+export default function BotsPage() {
+    return <EmptyCrew />;
+}
+
+export const meta: BunextPageModuleMeta = {
+    title: `Bots | ${SiteData["SiteName"]}`,
+    description: `Your crew of bots.`,
+};