Complete multi-source Beast format implementation

Major features implemented:
- Beast binary format parser with full Mode S/ADS-B decoding
- Multi-source data merger with intelligent signal-based fusion
- Advanced web frontend with 5 view modes (Map, Table, Stats, Coverage, 3D)
- Real-time WebSocket updates with sub-second latency
- Signal strength analysis and coverage heatmaps
- Debian packaging with systemd integration
- Production-ready deployment with security hardening

Technical highlights:
- Concurrent TCP clients with auto-reconnection
- CPR position decoding and aircraft identification
- Historical flight tracking with position trails
- Range circles and receiver location visualization
- Mobile-responsive design with professional UI
- REST API and WebSocket real-time updates
- Comprehensive build system and documentation

🤖 Generated with [Claude Code](https://claude.ai/code)

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

debian/DEBIAN/postinst

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -e
+
+case "$1" in
+    configure)
+        # Create skyview user and group if they don't exist
+        if ! getent group skyview >/dev/null 2>&1; then
+            addgroup --system skyview
+        fi
+        
+        if ! getent passwd skyview >/dev/null 2>&1; then
+            adduser --system --ingroup skyview --home /var/lib/skyview \
+                    --no-create-home --disabled-password skyview
+        fi
+        
+        # Create directories with proper permissions
+        mkdir -p /var/lib/skyview
+        mkdir -p /var/log/skyview
+        chown skyview:skyview /var/lib/skyview
+        chown skyview:skyview /var/log/skyview
+        chmod 755 /var/lib/skyview
+        chmod 755 /var/log/skyview
+        
+        # Set permissions on config file
+        if [ -f /etc/skyview/config.json ]; then
+            chown root:skyview /etc/skyview/config.json
+            chmod 640 /etc/skyview/config.json
+        fi
+        
+        # Enable and start the service
+        systemctl daemon-reload
+        systemctl enable skyview.service
+        
+        echo "SkyView has been installed and configured."
+        echo "Edit /etc/skyview/config.json to configure your dump1090 sources."
+        echo "Then run: systemctl start skyview"
+        ;;
+esac
+
+exit 0