feat: HomeLab CSS art hero with Proxmox, Switch, NAS

- Add homelab-device-hero component (Proxmox VE + Router icon, Switch, TrueNAS)
- Dashed lines for network connections between devices
- Custom not-found page (replace Next.js 404)
- Homelab page uses CSS hero instead of feature image

Co-authored-by: Cursor <cursoragent@cursor.com>

components/homelab-device-hero.tsx

@@ -0,0 +1,78 @@
+'use client';
+
+import { SiTruenas, SiProxmox } from 'react-icons/si';
+import { FiServer } from 'react-icons/fi';
+
+/**
+ * HomeLab 設備展示：Proxmox VE + VyOS、Switch、NAS (TrueNAS)
+ * 使用純 CSS 藝術，取代 HomeLab 頁的 feature_image
+ */
+export function HomeLabDeviceHero() {
+  return (
+    <div
+      className="homelab-device-hero -mx-4 mb-6 flex justify-center py-4 sm:-mx-12 sm:py-6 lg:-mx-20 lg:py-8 group-[.toc-open]:lg:-mx-4"
+      role="img"
+      aria-label="HomeLab 設備：Proxmox VE、VyOS、交換器、NAS (TrueNAS)"
+    >
+      <div className="homelab-device-scene w-full max-w-full">
+        <div className="homelab-rack">
+          {/* Proxmox VE + VyOS Host */}
+          <div className="homelab-router">
+            <div className="homelab-router-body">
+              <div className="homelab-router-leds">
+                <span className="homelab-led homelab-led-power" aria-hidden />
+                <span className="homelab-led homelab-led-wan" aria-hidden />
+                <span className="homelab-led homelab-led-lan" aria-hidden />
+              </div>
+              <div className="homelab-router-logos">
+                <SiProxmox className="homelab-proxmox-logo homelab-logo-svg" aria-label="Proxmox VE" />
+                <FiServer className="homelab-router-icon homelab-logo-svg" aria-label="VyOS Router" />
+              </div>
+            </div>
+          </div>
+
+          {/* 網路線 - 連接 Proxmox 與 Switch */}
+          <div className="homelab-cable" aria-hidden>
+            <span className="homelab-cable-line" />
+          </div>
+
+          {/* Switch */}
+          <div className="homelab-switch">
+            <div className="homelab-switch-body">
+              <div className="homelab-switch-ports">
+                {[1, 2].map((row) => (
+                  <div key={row} className="homelab-port-row">
+                    {Array.from({ length: 8 }).map((_, i) => (
+                      <div key={i} className="homelab-port">
+                        <span className="homelab-port-led homelab-port-led-active" aria-hidden />
+                      </div>
+                    ))}
+                  </div>
+                ))}
+              </div>
+            </div>
+          </div>
+
+          {/* 網路線 - 連接 Switch 與 NAS */}
+          <div className="homelab-cable" aria-hidden>
+            <span className="homelab-cable-line" />
+          </div>
+
+          {/* NAS - TrueNAS */}
+          <div className="homelab-nas">
+            <div className="homelab-nas-body">
+              <div className="homelab-nas-drives">
+                {[1, 2, 3, 4].map((i) => (
+                  <div key={i} className="homelab-drive-slot" aria-hidden />
+                ))}
+              </div>
+              <div className="homelab-nas-logo" aria-label="TrueNAS logo">
+                <SiTruenas className="homelab-truenas-logo" size={28} />
+              </div>
+            </div>
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}