feat: cream terminal redesign, English-only UI, autopilot launch fixes

- Redesign dashboard into a cream-paper + vermilion IBM Plex Mono terminal
  (live L2 order book, cost/liq map, WS K-line, signal matrix, orchestration
  topology, risk radar, execution log, current positions, equity curve)
- Convert all user-facing UI and backend strings/prompts from Chinese to
  English (multi-language retained, default English)
- Add /api/statistics/full endpoint + full-stats frontend wiring
- Fix Autopilot launch: reuse the existing trader instead of creating
  duplicates (eliminates repeat ~35s create cost and stale-trader 404s);
  launch sends 5m scan interval
- Fix unreadable toasts: cream theme with high-contrast text + per-type accent
- Silence background dashboard polls (getTraderConfig) to stop error-toast spam

web/src/components/common/Header.tsx

@@ -19,11 +19,11 @@ export function Header({ simple = false }: HeaderProps) {
               <img src="/icons/nofx.svg" alt="NoFx Logo" className="w-8 h-8" />
             </div>
             <div>
-              <h1 className="text-xl font-bold" style={{ color: '#EAECEF' }}>
+              <h1 className="text-xl font-bold" style={{ color: '#1A1813' }}>
                 {t('appTitle', language)}
               </h1>
               {!simple && (
-                <p className="text-xs mono" style={{ color: '#848E9C' }}>
+                <p className="text-xs mono" style={{ color: '#8A8478' }}>
                   {t('subtitle', language)}
                 </p>
               )}
@@ -33,26 +33,26 @@ export function Header({ simple = false }: HeaderProps) {
           {/* Right - Language Toggle (always show) */}
           <div
             className="flex gap-1 rounded p-1"
-            style={{ background: '#1E2329' }}
+            style={{ background: '#E8E2D5' }}
           >
             <button
               onClick={() => setLanguage('zh')}
               className="px-3 py-1.5 rounded text-xs font-semibold transition-all"
               style={
                 language === 'zh'
-                  ? { background: '#F0B90B', color: '#000' }
-                  : { background: 'transparent', color: '#848E9C' }
+                  ? { background: '#E0483B', color: '#F1ECE2' }
+                  : { background: 'transparent', color: '#8A8478' }
               }
             >
-              中文
+              Chinese
             </button>
             <button
               onClick={() => setLanguage('en')}
               className="px-3 py-1.5 rounded text-xs font-semibold transition-all"
               style={
                 language === 'en'
-                  ? { background: '#F0B90B', color: '#000' }
-                  : { background: 'transparent', color: '#848E9C' }
+                  ? { background: '#E0483B', color: '#F1ECE2' }
+                  : { background: 'transparent', color: '#8A8478' }
               }
             >
               EN
@@ -62,8 +62,8 @@ export function Header({ simple = false }: HeaderProps) {
               className="px-3 py-1.5 rounded text-xs font-semibold transition-all"
               style={
                 language === 'id'
-                  ? { background: '#F0B90B', color: '#000' }
-                  : { background: 'transparent', color: '#848E9C' }
+                  ? { background: '#E0483B', color: '#F1ECE2' }
+                  : { background: 'transparent', color: '#8A8478' }
               }
             >
               ID