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)/user-bubble.tsx

@@ -0,0 +1,12 @@
+import P from "@moduletrace/twui/layout/P";
+
+/**
+ * Ink bubble with paper text; inverts in dark mode.
+ */
+export default function UserBubble({ text }: { text: string }) {
+    return (
+        <P noMargin className="max-w-[80%] rounded-default-lg bg-ink text-on-ink px-4 py-3 text-sm leading-5 whitespace-pre-wrap break-words">
+            {text}
+        </P>
+    );
+}