Performance chart under positions; remove obsolete files

- PerfChart moves into the left column under Open Positions
  (half-width), balancing the radar column.

Cleanup:
- Design mockup pages (DesignMockups / DesignHorizon / DesignOrbit)
  and their routes removed - the redesign has shipped; the mockups
  live on in git history. Main bundle shrinks ~97 kB and the
  chunk-size warning goes away.
- frontend/tsconfig.tsbuildinfo untracked and gitignored (incremental
  build artifact that churned in every commit).
- Dead npm test / test:watch scripts removed - vitest was never a
  dependency; CI already skips the step via its vitest guard.

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

frontend/src/App.tsx

@@ -9,18 +9,12 @@ import SignalsPage from './pages/SignalsPage';
 import RegimePage from './pages/RegimePage';
 import TickerDetailPage from './pages/TickerDetailPage';
 import AdminPage from './pages/AdminPage';
-import DesignMockupsPage from './pages/DesignMockupsPage';
-import DesignHorizonPage from './pages/DesignHorizonPage';
-import DesignOrbitPage from './pages/DesignOrbitPage';
 
 export default function App() {
   return (
     <Routes>
       <Route path="/login" element={<LoginPage />} />
       <Route path="/register" element={<RegisterPage />} />
-      <Route path="/design-mockups" element={<DesignMockupsPage />} />
-      <Route path="/design-horizon" element={<DesignHorizonPage />} />
-      <Route path="/design-orbit" element={<DesignOrbitPage />} />
       <Route element={<ProtectedRoute />}>
         <Route element={<AppShell />}>
           <Route path="/" element={<DashboardPage />} />