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/prerm

@@ -0,0 +1,17 @@
+#!/bin/bash
+set -e
+
+case "$1" in
+    remove|upgrade|deconfigure)
+        # Stop and disable the service
+        if systemctl is-active --quiet skyview.service; then
+            systemctl stop skyview.service
+        fi
+        
+        if systemctl is-enabled --quiet skyview.service; then
+            systemctl disable skyview.service
+        fi
+        ;;
+esac
+
+exit 0