Redesign: phosphor-terminal identity and simplified 4-page structure

Information architecture (6 nav destinations -> 4):
- New Overview home: metric strip (live setups, high confidence,
  hit rate, expectancy), top-5 setups, watchlist pulse
- Market = Watchlist + Rankings merged as tabs; scoring weights
  moved into a collapsible disclosure
- Signals = Scanner + Performance merged as tabs (Setups | Track
  Record) with actions inside the panels
- Legacy routes redirect (/watchlist, /rankings, /scanner,
  /performance)

Visual identity:
- Warm ash-green dark palette replaces cold navy; citron lime
  accent replaces blue (Tailwind gray/blue remapped at config
  level so all components reskin)
- Primary buttons: lime with ink text; long/short stays
  emerald/red
- Typography: Bricolage Grotesque display, Instrument Sans body,
  IBM Plex Mono for all numerals incl. chart canvas labels
- Atmosphere: graph-paper grid + citron glow + film grain;
  pulsing brand dot; mono-numbered nav

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

frontend/src/App.tsx

@@ -3,11 +3,10 @@ import ProtectedRoute from './components/auth/ProtectedRoute';
 import AppShell from './components/layout/AppShell';
 import LoginPage from './pages/LoginPage';
 import RegisterPage from './pages/RegisterPage';
-import WatchlistPage from './pages/WatchlistPage';
+import DashboardPage from './pages/DashboardPage';
+import MarketPage from './pages/MarketPage';
+import SignalsPage from './pages/SignalsPage';
 import TickerDetailPage from './pages/TickerDetailPage';
-import ScannerPage from './pages/ScannerPage';
-import RankingsPage from './pages/RankingsPage';
-import PerformancePage from './pages/PerformancePage';
 import AdminPage from './pages/AdminPage';
 
 export default function App() {
@@ -17,12 +16,15 @@ export default function App() {
       <Route path="/register" element={<RegisterPage />} />
       <Route element={<ProtectedRoute />}>
         <Route element={<AppShell />}>
-          <Route path="/" element={<Navigate to="/watchlist" />} />
-          <Route path="/watchlist" element={<WatchlistPage />} />
+          <Route path="/" element={<DashboardPage />} />
+          <Route path="/market" element={<MarketPage />} />
+          <Route path="/signals" element={<SignalsPage />} />
           <Route path="/ticker/:symbol" element={<TickerDetailPage />} />
-          <Route path="/scanner" element={<ScannerPage />} />
-          <Route path="/rankings" element={<RankingsPage />} />
-          <Route path="/performance" element={<PerformancePage />} />
+          {/* Legacy routes from the old 6-page layout */}
+          <Route path="/watchlist" element={<Navigate to="/market" replace />} />
+          <Route path="/rankings" element={<Navigate to="/market?tab=rankings" replace />} />
+          <Route path="/scanner" element={<Navigate to="/signals" replace />} />
+          <Route path="/performance" element={<Navigate to="/signals?tab=track" replace />} />
           <Route element={<ProtectedRoute requireAdmin />}>
             <Route path="/admin" element={<AdminPage />} />
           </Route>