docs(spec): expand Phase 2B to polish foundation + form layout

Bundles patina palette shift, logo update (translucent gradient gem),
glass-card vocabulary across login/setup/fullscreen, and the original
two-column form layout. Updates relicario-logo.svg and -16.svg to the
patina palette.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

extension/icons/relicario-logo-16.svg

@@ -1,13 +1,13 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" fill="none">
   <defs>
     <radialGradient id="redThecaSm" cx="0.4" cy="0.35">
-      <stop offset="0%" stop-color="#9a1a1a"/>
-      <stop offset="100%" stop-color="#3a0a0a"/>
+      <stop offset="0%" stop-color="#7d2622"/>
+      <stop offset="100%" stop-color="#2c0d0a"/>
     </radialGradient>
     <linearGradient id="goldRingSm" x1="0" x2="1">
-      <stop offset="0%" stop-color="#d2ab43"/>
-      <stop offset="50%" stop-color="#f5d97a"/>
-      <stop offset="100%" stop-color="#7c5719"/>
+      <stop offset="0%" stop-color="#a88a4a"/>
+      <stop offset="50%" stop-color="#cdb47a"/>
+      <stop offset="100%" stop-color="#5a3f12"/>
     </linearGradient>
   </defs>
 
@@ -15,13 +15,13 @@
   <circle cx="8" cy="9" r="6.5" fill="url(#goldRingSm)"/>
   <circle cx="8" cy="9" r="4.8" fill="url(#redThecaSm)"/>
 
-  <!-- Asterisk-as-3-bars -->
-  <g transform="translate(8, 9)" stroke="#f5d97a" stroke-width="1.2" stroke-linecap="round">
+  <!-- Asterisk-as-3-bars (translucent) -->
+  <g transform="translate(8, 9)" stroke="#dac8a0" stroke-width="1.2" stroke-linecap="round" stroke-opacity="0.8">
     <line x1="0" y1="-3" x2="0" y2="3"/>
     <line x1="-2.6" y1="-1.5" x2="2.6" y2="1.5"/>
     <line x1="-2.6" y1="1.5" x2="2.6" y2="-1.5"/>
   </g>
-  <circle cx="8" cy="9" r="0.7" fill="#fff3cf"/>
+  <circle cx="8" cy="9" r="0.7" fill="#dac8a0"/>
 
   <!-- Fleur (3 tips) -->
   <path d="M 8 0 L 7.2 2.5 L 8.8 2.5 Z" fill="url(#goldRingSm)"/>