A warmer, friendlier admin: first pass

- The INBUXA palette on warm surfaces, softer cards, buttons and inputs, and
  self-hosted Inter and Space Grotesk.
- Each section's icon sits on a colored tile, colored by what the section is
  about.
- The sidebar gets a guide line for sub-pages and a labeled Management /
  Settings / Account switch, and folds to a rail of tiles (remembered).
- Every page has a header with its section's tile.
- Fields and pages with no label of their own are spelled out in words
  (defaultCertificateId becomes Default certificate ID).
- The dashboard greets you, and its stat cards wear colored tiles.
- Unavailable live numbers are a calm note, not an error.
- The cat appears in empty lists and while loading.
- Chart colors work again: they were hex values wrapped in hsl().

src/components/common/EmptyState.tsx

@@ -0,0 +1,20 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Coffey Labs
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { ReactNode } from 'react';
+import inbuxaMark from '@/assets/inbuxa-mark.png';
+
+/** Nothing to show yet: the cat, a line saying so, and what to do about it. */
+export function EmptyState({ title, hint, action }: { title: ReactNode; hint?: ReactNode; action?: ReactNode }) {
+  return (
+    <div className="flex flex-col items-center gap-2 px-6 py-12 text-center">
+      <img src={inbuxaMark} alt="" className="mb-1 h-14 w-auto opacity-90 grayscale-[15%]" />
+      <p className="font-display text-base font-semibold text-foreground">{title}</p>
+      {hint && <p className="max-w-sm text-sm text-muted-foreground">{hint}</p>}
+      {action && <div className="mt-2">{action}</div>}
+    </div>
+  );
+}