Add aircraft type classification with distinct icons

- Commercial aircraft: Green airplane icon (default)
- Cargo aircraft: Orange box icon (UPS, FedEx, etc.)
- Military aircraft: Red fighter-style icon (RCH, CNV, etc.)
- General aviation: Yellow light aircraft icon
- Ground aircraft: Gray circle with 'G' indicator
- Add visual legend on map showing aircraft type colors
- Aircraft type detection based on flight number patterns

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

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

static/css/style.css

@@ -124,6 +124,45 @@ body {
     background: #404040;
 }
 
+.legend {
+    position: absolute;
+    bottom: 10px;
+    left: 10px;
+    background: rgba(45, 45, 45, 0.95);
+    border: 1px solid #404040;
+    border-radius: 8px;
+    padding: 1rem;
+    z-index: 1000;
+    min-width: 150px;
+}
+
+.legend h4 {
+    margin: 0 0 0.5rem 0;
+    font-size: 0.9rem;
+    color: #ffffff;
+}
+
+.legend-item {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    margin-bottom: 0.25rem;
+    font-size: 0.8rem;
+}
+
+.legend-icon {
+    width: 16px;
+    height: 16px;
+    border-radius: 2px;
+    border: 1px solid #ffffff;
+}
+
+.legend-icon.commercial { background: #00ff88; }
+.legend-icon.cargo { background: #ff8c00; }
+.legend-icon.military { background: #ff4444; }
+.legend-icon.ga { background: #ffff00; }
+.legend-icon.ground { background: #888888; }
+
 .table-controls {
     display: flex;
     gap: 1rem;