feat: add React UI for rpm.lair.cafe

- Vite + React + SWC + TypeScript SPA with react-router and
  react-bootstrap
- Dark/light/system theme with Bootstrap 5.3 data-bs-theme
- Home page with repo setup instructions and copyable code blocks
- Package list and detail pages driven by packages.json
- Python script to generate packages.json from repodata XML
- Nginx config updated for SPA fallback, asset caching, removed
  autoindex
- New deploy-ui workflow triggered on ui/ or nginx config changes,
  requires runners with nvm label
- packages.json generation added to publish job after createrepo_c
- Runner setup docs for nvm and sequoia-sq added to readme

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/Home.tsx

@@ -0,0 +1,49 @@
+import { Card, Col, Row } from "react-bootstrap";
+import { CodeBlock } from "../components/CodeBlock.tsx";
+
+const GPG_KEY_URL = "https://rpm.lair.cafe/8b2023ce.gpg";
+
+const REPO_FILE = `[lair-cafe]
+name=lair.cafe RPM Repository
+baseurl=https://rpm.lair.cafe/fedora/$releasever/$basearch/
+enabled=1
+gpgcheck=1
+gpgkey=${GPG_KEY_URL}`;
+
+export function Home() {
+  return (
+    <>
+      <h1 className="mb-3">rpm.lair.cafe</h1>
+      <p className="lead mb-4">
+        Self-hosted RPM repository for Fedora, currently hosting CUDA-accelerated
+        builds of{" "}
+        <a href="https://github.com/EricLBuehler/mistral.rs">mistral.rs</a>.
+      </p>
+
+      <Row className="g-4">
+        <Col lg={12}>
+          <Card>
+            <Card.Body>
+              <Card.Title>Quick start</Card.Title>
+
+              <h6 className="mt-4">1. Import the signing key</h6>
+              <CodeBlock language="bash">
+                {`sudo rpm --import ${GPG_KEY_URL}`}
+              </CodeBlock>
+
+              <h6 className="mt-4">2. Add the repository</h6>
+              <CodeBlock language="bash">
+                {`sudo dnf config-manager addrepo --from-repofile=/dev/stdin <<'EOF'\n${REPO_FILE}\nEOF`}
+              </CodeBlock>
+
+              <h6 className="mt-4">3. Install a package</h6>
+              <CodeBlock language="bash">
+                {`sudo dnf install mistralrs-server-cuda13`}
+              </CodeBlock>
+            </Card.Body>
+          </Card>
+        </Col>
+      </Row>
+    </>
+  );
+}