fix(client): give the portal row an icon, and assert every gated nav has one

The §7.7 smoke, running the pair together: registering the player row without an
`icon` blanked the whole portal with React error #130, because core's
PlayerPortalLayout rendered `<n.icon />` unguarded. Core is guarded now
(website), and this is the other half — the row had an icon before it moved and
should have kept one.

A second glyph rather than reusing IconShard: these two rows sit in different
navs and each matched its neighbours before the extraction. The admin sidebar's
UO rows were gems; the portal's Characters row was a person beside Appeals'
shield and Account's gear. Matching the nav a row lands in is the whole reason
`icon` is in the contract.

`registration.test.js` now asserts it for admin AND player rows, which is the
cheap place to catch the next one. The public header is text buttons and is
deliberately excluded.

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

client/src/entry.jsx

@@ -18,7 +18,7 @@
 // size and it is the one thing this seam cannot have.
 
 import { registry, coreApiVersion } from './core.js'
-import { IconShard } from './icons.jsx'
+import { IconShard, IconUser } from './icons.jsx'
 import { useShardFlags } from './lib/useShardFeatures.js'
 
 // Public pages — the twelve that used to live at /site/*.
@@ -159,7 +159,7 @@ registry.registerNav(ID, {
   area: 'player',
   // Order 0: Characters is the portal's first row today, and with the module
   // installed it is also what core's `/player` index resolves to.
-  items: [{ label: 'Characters', to: '/player/uo/characters', order: 0 }],
+  items: [{ label: 'Characters', to: '/player/uo/characters', icon: IconUser, order: 0 }],
 })
 
 // ── Feature provider ───────────────────────────────────────────────────────

client/src/icons.jsx

@@ -35,4 +35,32 @@ export const IconShard = () => (
   </Icon>
 )
 
+/**
+ * A figure — the glyph core used for the portal's "Characters" row.
+ *
+ * A second icon rather than reusing IconShard, because these two rows sit in
+ * different navs and each matched its neighbours before the extraction: the
+ * admin sidebar's UO rows were all gems, and the portal's Characters row was a
+ * person beside Appeals' shield and Account's gear. Copied from core's
+ * PlayerPortalLayout, which uses a 16px frame and a heavier stroke than the
+ * admin one — matching the nav a row lands in is the whole reason `icon` exists.
+ */
+export const IconUser = () => (
+  <svg
+    width="16"
+    height="16"
+    viewBox="0 0 24 24"
+    fill="none"
+    stroke="currentColor"
+    strokeWidth="2"
+    strokeLinecap="round"
+    strokeLinejoin="round"
+    aria-hidden="true"
+    focusable="false"
+  >
+    <circle cx="12" cy="8" r="4" />
+    <path d="M4 21a8 8 0 0 1 16 0" />
+  </svg>
+)
+
 export default IconShard