feat(client): the whole client half (phase 3, slice 3)

The 35 files behind twelve public pages, seven admin views, two player views
and three core-page extensions, ported onto `window.__rg`. Every one of them
imports exactly the seven kit members plus `lib/format.js`, which is the
finding §2.7.1 predicted and this confirms.

`client/src/core.js` is the port mechanism, and unlike the server's it is a
plain read: `window.__rg` is published before any module chunk evaluates, so
there is no gap to defer around and a ported component keeps its ordinary
import shape. `client/src/api.js` rebuilds the UO namespaces over the request
primitive — same URLs, because §1.2 freezes the API surface.

SPA paths changed and API paths did not. `/site/shard` is `/uo/shard`, and the
admin paths lost their now-redundant `shard-` prefixes (`/admin/uo/ops`), a
clean break being the only moment that is free.

`shim/rg.js` becomes the single reader of the global, so the "core did not
publish its dependencies" message is reachable from whichever module the
bundler happens to touch first rather than from whichever one is imported
first — a guarantee that used to last until someone sorted the imports.

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

client/src/routes/player/PlayerCharacter.jsx

@@ -0,0 +1,28 @@
+import { useParams, Link } from 'react-router-dom'
+import CharacterSheet from '../../components/CharacterSheet.jsx'
+import api from '../../api.js'
+import { ErrorState, Loading, useAsync } from '../../core.js'
+
+// A player's character sheet inside the portal. Owner-checked: the endpoint only
+// returns a sheet for a character on an account linked to the caller.
+export default function PlayerCharacter() {
+  const { serial } = useParams()
+  const { loading, error, data } = useAsync(() => api.player.shard.char(serial), [serial])
+  const restarting = error && error.status === 503
+  const forbidden = error && error.status === 403
+
+  return (
+    <div>
+      <p style={{ margin: '0 0 18px' }}>
+        <Link to="/player/uo/characters" className="sans" style={{ color: 'var(--accent)', textDecoration: 'none', fontSize: '0.86rem' }}>
+          ← Back to characters
+        </Link>
+      </p>
+      {loading && <Loading />}
+      {restarting && <ErrorState message="The game server is restarting — try again shortly." />}
+      {forbidden && <ErrorState message="That character is not on an account linked to you." />}
+      {error && !restarting && !forbidden && <ErrorState message="Could not load that character right now." />}
+      {!loading && !error && data && <CharacterSheet char={data} />}
+    </div>
+  )
+}