Let staff link their own characters + share the game-accounts UI

- Backend: /admin/shard/{link,accounts,roster/:account,vendors/:account} —
  staff self-service, reusing the player/shard controller (it keys off
  req.user.id, so the same handlers serve any logged-in role). Swagger under
  Admin · Account; spec regenerated.
- components/GameAccounts.jsx: the link-prompt + character-roster UI extracted
  into one reusable component parametrized by an api scope and a charTo(serial)
  route builder.
- PlayerCharacters now renders it (player scope → /player/char/:serial).
- Admin: "My Characters" nav item + /admin/characters (AdminCharacters) and
  /admin/characters/:serial (AdminCharacter, in-shell sheet), using the admin
  self-service scope. api.admin.shard.* added.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011qPmpmVH1xGCiZoz9m9vW3

client/src/App.jsx

@@ -36,6 +36,8 @@ import ActivityAdmin from './routes/admin/views/ActivityAdmin.jsx'
 import BotActivityAdmin from './routes/admin/views/BotActivityAdmin.jsx'
 import DiscordBotAdmin from './routes/admin/views/DiscordBotAdmin.jsx'
 import ShardAdmin from './routes/admin/views/ShardAdmin.jsx'
+import AdminCharacters from './routes/admin/views/AdminCharacters.jsx'
+import AdminCharacter from './routes/admin/views/AdminCharacter.jsx'
 import AuthProvidersAdmin from './routes/admin/views/AuthProvidersAdmin.jsx'
 import UsersAdmin from './routes/admin/views/UsersAdmin.jsx'
 import AccountAdmin from './routes/admin/views/AccountAdmin.jsx'
@@ -118,6 +120,8 @@ export default function App() {
             <Route path="bot-activity" element={<BotActivityAdmin />} />
             <Route path="discord-bot" element={<DiscordBotAdmin />} />
             <Route path="shard" element={<ShardAdmin />} />
+            <Route path="characters" element={<AdminCharacters />} />
+            <Route path="characters/:serial" element={<AdminCharacter />} />
             <Route path="auth-providers" element={<AuthProvidersAdmin />} />
             <Route path="users" element={<UsersAdmin />} />
             <Route path="account" element={<AccountAdmin />} />