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/.env.example

@@ -0,0 +1,25 @@
+# General
+COMPOSE_PROJECT_NAME=bordanlage
+DEV=true
+
+# Spotify Connect
+SPOTIFY_NAME=Bordanlage
+SPOTIFY_BITRATE=320
+SPOTIFY_CACHE_SIZE=1024
+
+# Boat Info
+BOAT_NAME=My Yacht
+BOAT_MMSI=123456789
+
+# Paths
+MUSIC_PATH=./music
+
+# Jellyfin API Key (set after first run)
+JELLYFIN_API_KEY=
+
+# Service URLs (used by dashboard)
+VITE_SNAPCAST_HOST=localhost
+VITE_SIGNALK_HOST=localhost
+VITE_MOPIDY_HOST=localhost
+VITE_JELLYFIN_HOST=localhost
+VITE_PORTAINER_HOST=localhost