fix: overhaul PWA icons with v2 suffix to bust all cache layers

- Redesign favicon SVG with gradient border matching splash screen
- Rename all icon files with -v2 suffix to bypass browser/SW/PWA caches
- Delete 9 old/duplicate icon files (~13MB removed)
- Add nginx cache-control headers for icons and manifest
- Rename assets-cache to assets-cache-v2 to orphan stale SW cache
- Update all HTML, manifest, and component icon references

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

neode-ui/public/assets/icon/favico-black-v2.svg

@@ -0,0 +1,31 @@
+<svg width="1024" height="1024" viewBox="0 0 1024 1024" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <defs>
+    <radialGradient id="bgGrad" cx="50%" cy="45%" r="55%">
+      <stop offset="0%" stop-color="#1a1a1a"/>
+      <stop offset="100%" stop-color="#050505"/>
+    </radialGradient>
+    <linearGradient id="borderGrad" x1="0" y1="0" x2="1024" y2="1024" gradientUnits="userSpaceOnUse">
+      <stop offset="0%" stop-color="#ffffff" stop-opacity="0.55"/>
+      <stop offset="50%" stop-color="#888888" stop-opacity="0.25"/>
+      <stop offset="100%" stop-color="#000000" stop-opacity="0.7"/>
+    </linearGradient>
+    <radialGradient id="glassGlow" cx="35%" cy="30%" r="50%">
+      <stop offset="0%" stop-color="#ffffff" stop-opacity="0.06"/>
+      <stop offset="100%" stop-color="#000000" stop-opacity="0"/>
+    </radialGradient>
+  </defs>
+
+  <!-- Background circle -->
+  <circle cx="512" cy="512" r="484" fill="url(#bgGrad)"/>
+
+  <!-- Glass glow highlight (top-left) -->
+  <circle cx="512" cy="512" r="460" fill="url(#glassGlow)"/>
+
+  <!-- Gradient border ring (white-to-dark, like logo-gradient-border CSS) -->
+  <circle cx="512" cy="512" r="484" fill="none" stroke="url(#borderGrad)" stroke-width="16"/>
+
+  <!-- The "A" logo — pixel-art style, centered and scaled -->
+  <g transform="translate(160, 168) scale(0.69)">
+    <path d="M357.614 388.936V318H428.621V388.936H357.614ZM436.152 388.936V318H508.234V388.936H436.152ZM515.766 388.936V318H587.848V388.936H515.766ZM595.379 388.936V318H666.386V388.936H595.379ZM595.379 468.471V396.46H666.386V468.471H595.379ZM673.917 468.471V396.46H746V468.471H673.917ZM278 548.006V475.994H350.083V548.006H278ZM357.614 548.006V475.994H428.621V548.006H357.614ZM436.152 548.006V475.994H508.234V548.006H436.152ZM515.766 548.006V475.994H587.848V548.006H515.766ZM595.379 548.006V475.994H666.386V548.006H595.379ZM673.917 548.006V475.994H746V548.006H673.917ZM278 626.465V555.529H350.083V626.465H278ZM357.614 626.465V555.529H428.621V626.465H357.614ZM595.379 626.465V555.529H666.386V626.465H595.379ZM673.917 626.465V555.529H746V626.465H673.917ZM357.614 706V633.989H428.621V706H357.614ZM436.152 706V633.989H508.234V706H436.152ZM515.766 706V633.989H587.848V706H515.766ZM595.379 706V633.989H666.386V706H595.379Z" fill="white"/>
+  </g>
+</svg>

neode-ui/public/assets/icon/favico-black.svg

@@ -1,4 +0,0 @@
-<svg width="1024" height="1024" viewBox="0 0 1024 1024" fill="none" xmlns="http://www.w3.org/2000/svg">
-<rect width="1024" height="1024" fill="#030202"/>
-<path d="M357.614 388.936V318H428.621V388.936H357.614ZM436.152 388.936V318H508.234V388.936H436.152ZM515.766 388.936V318H587.848V388.936H515.766ZM595.379 388.936V318H666.386V388.936H595.379ZM595.379 468.471V396.46H666.386V468.471H595.379ZM673.917 468.471V396.46H746V468.471H673.917ZM278 548.006V475.994H350.083V548.006H278ZM357.614 548.006V475.994H428.621V548.006H357.614ZM436.152 548.006V475.994H508.234V548.006H436.152ZM515.766 548.006V475.994H587.848V548.006H515.766ZM595.379 548.006V475.994H666.386V548.006H595.379ZM673.917 548.006V475.994H746V548.006H673.917ZM278 626.465V555.529H350.083V626.465H278ZM357.614 626.465V555.529H428.621V626.465H357.614ZM595.379 626.465V555.529H666.386V626.465H595.379ZM673.917 626.465V555.529H746V626.465H673.917ZM357.614 706V633.989H428.621V706H357.614ZM436.152 706V633.989H508.234V706H436.152ZM515.766 706V633.989H587.848V706H515.766ZM595.379 706V633.989H666.386V706H595.379Z" fill="white"/>
-</svg>

neode-ui/public/assets/img/l484-icon.svg

@@ -1,17 +0,0 @@
-<svg width="285" height="273" viewBox="0 0 285 273" fill="none" xmlns="http://www.w3.org/2000/svg">
-<g filter="url(#filter0_d_145_9)">
-<path d="M67.6045 215.234H154.772V240.824H28L77.7109 127.559L131.736 76.2861L67.6045 215.234ZM198.893 146.688H256.594L213.508 240.824H171.984V172.604H114.283L156.588 76.7314L177.74 50.3652L198.893 24V146.688ZM198.893 214.361L217.207 172.604H198.893V214.361ZM153.67 146.688H171.984V104.929L153.67 146.688Z" fill="white"/>
-</g>
-<defs>
-<filter id="filter0_d_145_9" x="0" y="0" width="284.594" height="272.824" filterUnits="userSpaceOnUse" color-interpolation-filters="sRGB">
-<feFlood flood-opacity="0" result="BackgroundImageFix"/>
-<feColorMatrix in="SourceAlpha" type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 127 0" result="hardAlpha"/>
-<feOffset dy="4"/>
-<feGaussianBlur stdDeviation="14"/>
-<feComposite in2="hardAlpha" operator="out"/>
-<feColorMatrix type="matrix" values="0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.25 0"/>
-<feBlend mode="normal" in2="BackgroundImageFix" result="effect1_dropShadow_145_9"/>
-<feBlend mode="normal" in="SourceGraphic" in2="effect1_dropShadow_145_9" result="shape"/>
-</filter>
-</defs>
-</svg>