feat: add DeepVoidBackground and update UI theme across pages

- Add DeepVoidBackground component with animated gradient effects
- Apply nofx theme classes to StrategyStudioPage, AITradersPage, etc.
- Update styling for consistent dark theme with gold accents
- Add PageNotFound and TraderDashboardPage components

web/src/pages/PageNotFound.tsx

@@ -0,0 +1,43 @@
+import { DeepVoidBackground } from '../components/DeepVoidBackground'
+import { AlertCircle, Home } from 'lucide-react'
+
+export function PageNotFound() {
+    return (
+        <DeepVoidBackground className="flex items-center justify-center text-center p-4">
+            <div className="bg-nofx-bg border border-nofx-gold/20 p-8 rounded-lg max-w-md w-full relative overflow-hidden group">
+
+                {/* Background Grid inside Card */}
+                <div className="absolute inset-0 bg-[linear-gradient(to_right,#80808008_1px,transparent_1px),linear-gradient(to_bottom,#80808008_1px,transparent_1px)] bg-[size:16px_16px] pointer-events-none"></div>
+
+                <div className="relative z-10 flex flex-col items-center gap-6">
+                    <div className="relative">
+                        <div className="absolute inset-0 bg-red-500/20 blur-xl animate-pulse"></div>
+                        <AlertCircle size={64} className="text-nofx-danger relative z-10" />
+                    </div>
+
+                    <div className="space-y-2">
+                        <h1 className="text-4xl font-bold font-mono tracking-tighter text-white">
+                            404
+                        </h1>
+                        <div className="text-xs uppercase tracking-[0.3em] text-nofx-danger font-mono border-b border-nofx-danger/30 pb-2 inline-block">
+                            SIGNAL_LOST
+                        </div>
+                    </div>
+
+                    <p className="text-sm text-nofx-text-muted font-mono leading-relaxed">
+                        The requested coordinates do not exist in the current sector. The page may have been moved, deleted, or never existed in this timeline.
+                    </p>
+
+                    <a
+                        href="/"
+                        className="flex items-center gap-2 px-6 py-3 bg-nofx-gold text-black font-bold text-sm uppercase tracking-widest rounded hover:bg-yellow-400 transition-all shadow-neon hover:shadow-[0_0_20px_rgba(240,185,11,0.4)] group mt-4"
+                    >
+                        <Home size={16} />
+                        <span>RETURN_BASE</span>
+                        <span className="opacity-0 group-hover:opacity-100 transition-opacity -ml-2 group-hover:ml-0">-&gt;</span>
+                    </a>
+                </div>
+            </div>
+        </DeepVoidBackground>
+    )
+}