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/components/general/stone-eye-arc.tsx

@@ -0,0 +1,25 @@
+import { StoneEyes } from "@/src/data/stone-geometry";
+
+type Props = {
+    cx: number;
+    cy: number;
+    className?: string;
+};
+
+/**
+ * Upward arc eye, drawn as a stroke in the eye colour.
+ */
+export default function StoneEyeArc({ cx, cy, className }: Props) {
+    const r = StoneEyes.radius;
+    const base = cy + r * 0.4;
+
+    return (
+        <path
+            d={`M ${cx - r} ${base} A ${r} ${r} 0 0 1 ${cx + r} ${base}`}
+            fill="none"
+            strokeWidth={2.6}
+            strokeLinecap="round"
+            className={className}
+        />
+    );
+}