Fix card links on index pages: add section prefix to local hrefs

Links like /proxmox/ were missing the section prefix (e.g. /infra/proxmox/)
since all sites now share a single Eleventy build at root.

smarthome/index.njk

@@ -9,19 +9,19 @@ sections:
     cards:
       - title: "Home dashboard"
         summary: "Lighting, music, and Tasmota device control shown on the home dashboard."
-        href: "/home-dashboard-controls/"
+        href: "/smarthome/home-dashboard-controls/"
         emoji: "🎛️"
       - title: "Tasmota & energy monitoring"
         summary: "Smart plugs and power monitoring across the flat, feeding daily usage stats."
-        href: "/tasmota-energy/"
+        href: "/smarthome/tasmota-energy/"
         emoji: "⚡"
       - title: "HomematicIP + MQTT"
         summary: "How HomematicIP room sensors are bridged into MQTT and stored in InfluxDB."
-        href: "/homematic-mqtt/"
+        href: "/smarthome/homematic-mqtt/"
         emoji: "📡"
       - title: "Balkon Pi"
         summary: "Balcony sensor, lighting, and audio automation unit."
-        href: "/balkonpi/"
+        href: "/smarthome/balkonpi/"
         emoji: "🌿"
   - heading: "Dashboards & Hardware"
     cards:
@@ -39,7 +39,7 @@ sections:
         emoji: "🖥️"
       - title: "Air quality dashboard"
         summary: "Real-time temperature and humidity monitoring across all rooms with historical charts."
-        href: "/air-quality/"
+        href: "/smarthome/air-quality/"
         emoji: "🌡️"
   - heading: "Personal services"
     cards:
@@ -63,19 +63,19 @@ sections:
     cards:
       - title: "AirPlay audio"
         summary: "Multi-room AirPlay receivers with software volume boost."
-        href: "/airplay-audio/"
+        href: "/smarthome/airplay-audio/"
         emoji: "🔊"
       - title: "OctoPrint"
         summary: "Remote 3D printer control and camera streaming."
-        href: "/octoprint/"
+        href: "/smarthome/octoprint/"
         emoji: "🖨️"
       - title: "YouTube archiving"
         summary: "TubeArchivist and TubeSync for self-hosted YouTube downloading on the Synology."
-        href: "/tubearchivist/"
+        href: "/smarthome/tubearchivist/"
         emoji: "📺"
       - title: "Kids RFID MP3 Player"
         summary: "Arduino-based audio player for kids using RFID cards, built as a custom alternative to Hoerbert."
-        href: "/kids-rfid-player/"
+        href: "/smarthome/kids-rfid-player/"
         emoji: "🎵"
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 <p class="site-intro">The heart of the homelab. Home Assistant, MQTT sensors, dashboards, and automation projects that make everyday life a little more interesting.</p>