Initial implementation: Bordanlage boat onboard system

Complete multiroom audio + navigation dashboard:
- Docker stack: SignalK, Snapcast (4 zones), librespot, shairport-sync, Mopidy, Jellyfin, Portainer
- React 18 + Vite dashboard with nautical dark theme
- Full mock system (SignalK NMEA simulation, Snapcast zones, Mopidy player)
- Real API clients for all services with reconnect logic
- SVG instruments: Compass, WindRose, Gauge, DepthSounder, SpeedLog
- Pages: Overview, Navigation, Audio (zones/radio/library), Systems
- Dev mode runs fully without hardware (make dev)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bordanlage/docker-compose.dev.yml

@@ -0,0 +1,58 @@
+version: "3.9"
+
+# Development override – run without any hardware.
+# Usage: docker compose -f docker-compose.yml -f docker-compose.dev.yml up -d
+
+services:
+
+  signalk:
+    environment:
+      - SIGNALK_DEMO=true   # Built-in demo NMEA data generator
+
+  # Spotify Connect still works over TCP on dev (no host network needed)
+  librespot:
+    environment:
+      - LIBRESPOT_DISABLE_DISCOVERY=false
+    ports:
+      - "57621:57621/udp"
+      - "57621:57621/tcp"
+
+  # avahi container for AirPlay mDNS discovery on Mac/Windows
+  avahi:
+    image: flungo/avahi
+    restart: unless-stopped
+    network_mode: host
+    volumes:
+      - /var/run/dbus:/var/run/dbus
+
+  # Null-player zones – no audio hardware needed
+  zone-salon:
+    command: snapclient --host snapserver --hostID zone-salon --player null
+
+  zone-cockpit:
+    command: snapclient --host snapserver --hostID zone-cockpit --player null
+
+  zone-bug:
+    command: snapclient --host snapserver --hostID zone-bug --player null
+
+  zone-heck:
+    command: snapclient --host snapserver --hostID zone-heck --player null
+
+  # Vite dev server with HMR instead of built nginx image
+  dashboard:
+    build: .
+    image: node:20-alpine
+    working_dir: /app
+    volumes:
+      - ./dashboard:/app
+      - /app/node_modules
+    command: sh -c "npm install && npm run dev -- --host 0.0.0.0 --port 8080"
+    ports:
+      - "8080:8080"
+    environment:
+      - VITE_SNAPCAST_HOST=localhost
+      - VITE_SIGNALK_HOST=localhost
+      - VITE_MOPIDY_HOST=localhost
+      - VITE_JELLYFIN_HOST=localhost
+    # Override the build-based image
+    image: node:20-alpine