[DESIGN-005] Replace illustrations with custom hero images (feat)

- Added custom SVG illustrations (shield and person with laptop)
- Replaced generic illustration with branded hero image
- Shield decoration in background with rotation animation
- Updated floating card to use shield icon
- Changed colors to match new illustrations (gold/orange shield)
- Person with laptop matches brand identity
- All images stored in assets/ for local control

assets/hero-shield.svg

@@ -0,0 +1,19 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 250 300">
+  <!-- Shield gradient -->
+  <defs>
+    <linearGradient id="shieldGrad" x1="0%" y1="0%" x2="0%" y2="100%">
+      <stop offset="0%" style="stop-color:#F59E0B;stop-opacity:1" />
+      <stop offset="50%" style="stop-color:#B8860B;stop-opacity:1" />
+      <stop offset="100%" style="stop-color:#1e3a8a;stop-opacity:1" />
+    </linearGradient>
+  </defs>
+  <!-- Outer shield -->
+  <path d="M125 10 C80 10, 40 20, 20 40 C20 120, 40 220, 125 280 C210 220, 230 120, 230 40 C210 20, 170 10, 125 10 Z" 
+        fill="url(#shieldGrad)" stroke="#D97706" stroke-width="3"/>
+  <!-- Inner shield -->
+  <path d="M125 40 C95 40, 70 47, 55 60 C55 120, 70 200, 125 250 C180 200, 195 120, 195 60 C180 47, 155 40, 125 40 Z" 
+        fill="#4B5563" opacity="0.8"/>
+  <!-- Check mark -->
+  <path d="M90 130 L110 160 L165 100" 
+        stroke="#10B981" stroke-width="12" stroke-linecap="round" stroke-linejoin="round" fill="none"/>
+</svg>