fix: use the ChefHat logo mark as favicon

app/icon.svg (Next.js auto-detected favicon convention) now uses the
same ChefHat glyph as the nav header logo instead of the default
Next.js placeholder. Also updated the PWA manifest icons to match so
favicon/logo/install-icon are all the same mark.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/icon.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="32" height="32">
+  <rect width="24" height="24" rx="5" fill="#18181b"/>
+  <g transform="translate(2.5, 2.5) scale(0.79)" fill="none" stroke="#fafafa" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+    <path d="M17 21a1 1 0 0 0 1-1v-5.35c0-.457.316-.844.727-1.041a4 4 0 0 0-2.134-7.589 5 5 0 0 0-9.186 0 4 4 0 0 0-2.134 7.588c.411.198.727.585.727 1.041V20a1 1 0 0 0 1 1Z"/>
+    <path d="M6 17h12"/>
+  </g>
+</svg>

apps/web/public/icon-192.svg

@@ -1,8 +1,7 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 192 192" width="192" height="192">
   <rect width="192" height="192" rx="36" fill="#18181b"/>
-  <circle cx="96" cy="96" r="34" fill="none" stroke="#fafafa" stroke-width="8"/>
-  <g fill="#fafafa">
-    <rect x="46" y="44" width="8" height="104" rx="4"/>
-    <rect x="138" y="44" width="8" height="104" rx="4"/>
+  <g transform="translate(36, 36) scale(5)" fill="none" stroke="#fafafa" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round">
+    <path d="M17 21a1 1 0 0 0 1-1v-5.35c0-.457.316-.844.727-1.041a4 4 0 0 0-2.134-7.589 5 5 0 0 0-9.186 0 4 4 0 0 0-2.134 7.588c.411.198.727.585.727 1.041V20a1 1 0 0 0 1 1Z"/>
+    <path d="M6 17h12"/>
   </g>
 </svg>

apps/web/public/icon-512.svg

@@ -1,8 +1,7 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="512" height="512">
   <rect width="512" height="512" rx="96" fill="#18181b"/>
-  <circle cx="256" cy="256" r="90" fill="none" stroke="#fafafa" stroke-width="20"/>
-  <g fill="#fafafa">
-    <rect x="122" y="118" width="20" height="276" rx="10"/>
-    <rect x="370" y="118" width="20" height="276" rx="10"/>
+  <g transform="translate(96, 96) scale(13.33)" fill="none" stroke="#fafafa" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round">
+    <path d="M17 21a1 1 0 0 0 1-1v-5.35c0-.457.316-.844.727-1.041a4 4 0 0 0-2.134-7.589 5 5 0 0 0-9.186 0 4 4 0 0 0-2.134 7.588c.411.198.727.585.727 1.041V20a1 1 0 0 0 1 1Z"/>
+    <path d="M6 17h12"/>
   </g>
 </svg>