Extract aircraft SVG icons to external files and add dynamic marker updates

- Extract all aircraft type SVG designs to separate files in /static/icons/
- Add icon caching system with async loading and fallback mechanisms
- Implement dynamic marker icon updates when aircraft properties change
- Detect and respond to aircraft type/category, ground status, and rotation changes
- Use currentColor in SVG files for dynamic color application
- Maintain performance with intelligent change detection (5° rotation threshold)
- Support real-time marker updates for weight class transitions and ADS-B changes

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

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

assets/static/icons/cargo.svg

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Wide-body cargo aircraft shape -->
+    <path d="M0,-12 L-10,8 L-3,8 L0,12 L3,8 L10,8 Z" fill="currentColor"/>
+    <!-- Fuselage bulk -->
+    <rect x="-2" y="-6" width="4" height="8" fill="currentColor"/>
+  </g>
+</svg>

assets/static/icons/commercial.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Standard commercial aircraft shape -->
+    <path d="M0,-12 L-8,8 L-2,8 L0,12 L2,8 L8,8 Z" fill="currentColor"/>
+  </g>
+</svg>

assets/static/icons/ga.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Small general aviation aircraft -->
+    <path d="M0,-10 L-5,6 L-1,6 L0,10 L1,6 L5,6 Z" fill="currentColor"/>
+  </g>
+</svg>

assets/static/icons/ground.svg

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Ground vehicle - truck/car shape -->
+    <rect x="-6" y="-4" width="12" height="8" fill="currentColor" rx="2"/>
+    <!-- Wheels -->
+    <circle cx="-3" cy="2" r="2" fill="#333"/>
+    <circle cx="3" cy="2" r="2" fill="#333"/>
+  </g>
+</svg>

assets/static/icons/helicopter.svg

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Rotor disc -->
+    <circle cx="0" cy="0" r="10" fill="none" stroke="currentColor" stroke-width="1" opacity="0.3"/>
+    <!-- Main body -->
+    <path d="M0,-8 L-6,6 L-1,6 L0,8 L1,6 L6,6 Z" fill="currentColor"/>
+    <!-- Rotor mast -->
+    <path d="M0,-6 L0,-10" stroke="currentColor" stroke-width="2"/>
+    <path d="M0,6 L0,8" stroke="currentColor" stroke-width="2"/>
+  </g>
+</svg>

assets/static/icons/military.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="32" height="32" viewBox="0 0 32 32" xmlns="http://www.w3.org/2000/svg">
+  <g transform="translate(16,16)">
+    <!-- Swept-wing fighter jet shape -->
+    <path d="M0,-12 L-4,2 L-8,8 L-2,6 L0,12 L2,6 L8,8 L4,2 Z" fill="currentColor"/>
+  </g>
+</svg>