fix: graceful HTTP shutdown, add ErrorBoundary, fix chart responsive height

- main.go: call server.Shutdown() on SIGTERM/SIGINT to drain in-flight requests
- Add React ErrorBoundary component (catches render crashes, shows retry UI)
- Wrap main content area and settings page with ErrorBoundary
- Fix ChartTabs.tsx: replace runtime window.innerWidth check with Tailwind responsive class (h-[500px] md:h-[600px])
- Restarted backend with latest build (health endpoint now returns proper timestamp)

main.go

@@ -181,6 +181,12 @@ func main() {
 	<-quit
 	logger.Info("📴 Shutdown signal received, closing system...")
 
+	// Gracefully shutdown HTTP server (drain in-flight requests)
+	if err := server.Shutdown(); err != nil {
+		logger.Warnf("⚠️ HTTP server shutdown error: %v", err)
+	}
+	logger.Info("✅ HTTP server stopped")
+
 	// Stop all traders
 	traderManager.StopAll()
 	logger.Info("✅ System shut down safely")

web/src/App.tsx

@@ -18,6 +18,7 @@ import { StrategyMarketPage } from './pages/StrategyMarketPage'
 import { DataPage } from './pages/DataPage'
 import { LoginRequiredOverlay } from './components/auth/LoginRequiredOverlay'
 import HeaderBar from './components/common/HeaderBar'
+import { ErrorBoundary } from './components/common/ErrorBoundary'
 import { LanguageProvider, useLanguage } from './contexts/LanguageContext'
 import { AuthProvider, useAuth } from './contexts/AuthContext'
 import { ConfirmDialogProvider } from './components/common/ConfirmDialog'
@@ -396,7 +397,9 @@ function App() {
           onLoginRequired={handleLoginRequired}
           onPageChange={navigateToPage}
         />
-        <SettingsPage />
+        <ErrorBoundary>
+          <SettingsPage />
+        </ErrorBoundary>
       </div>
     )
   }
@@ -474,6 +477,7 @@ function App() {
 
       {/* Main Content with Page Transitions */}
       <main className="min-h-screen pt-16">
+        <ErrorBoundary>
         <AnimatePresence mode="wait">
           <motion.div
             key={currentPage}
@@ -536,6 +540,7 @@ function App() {
             )}
           </motion.div>
         </AnimatePresence>
+        </ErrorBoundary>
       </main>
 
       {/* Footer */}

web/src/components/charts/ChartTabs.tsx

@@ -144,8 +144,7 @@ export function ChartTabs({ traderId, selectedSymbol, updateKey, exchangeId }: C
 
 
   return (
-    <div className={`nofx-glass rounded-lg border border-white/5 relative z-10 w-full flex flex-col transition-all duration-300 ${typeof window !== 'undefined' && window.innerWidth < 768 ? 'h-[500px]' : 'h-[600px]'
-      }`}>
+    <div className="nofx-glass rounded-lg border border-white/5 relative z-10 w-full flex flex-col transition-all duration-300 h-[500px] md:h-[600px]">
       {/* 
         Premium Professional Toolbar 
         Mobile: Single row, horizontal scroll with gradient mask

web/src/components/common/ErrorBoundary.tsx

@@ -0,0 +1,61 @@
+import { Component, type ReactNode } from 'react'
+import { AlertTriangle, RefreshCw } from 'lucide-react'
+
+interface Props {
+  children: ReactNode
+  fallback?: ReactNode
+}
+
+interface State {
+  hasError: boolean
+  error: Error | null
+}
+
+export class ErrorBoundary extends Component<Props, State> {
+  constructor(props: Props) {
+    super(props)
+    this.state = { hasError: false, error: null }
+  }
+
+  static getDerivedStateFromError(error: Error): State {
+    return { hasError: true, error }
+  }
+
+  componentDidCatch(error: Error, info: React.ErrorInfo) {
+    console.error('[ErrorBoundary] Uncaught error:', error, info.componentStack)
+  }
+
+  handleReset = () => {
+    this.setState({ hasError: false, error: null })
+  }
+
+  render() {
+    if (this.state.hasError) {
+      if (this.props.fallback) return this.props.fallback
+
+      return (
+        <div className="flex flex-col items-center justify-center min-h-[300px] p-8 text-center">
+          <AlertTriangle className="w-12 h-12 text-amber-400 mb-4" />
+          <h2 className="text-xl font-semibold text-white mb-2">Something went wrong</h2>
+          <p className="text-white/60 mb-1 max-w-md text-sm">
+            An unexpected error occurred. You can try refreshing this section.
+          </p>
+          {this.state.error && (
+            <p className="text-red-400/80 text-xs font-mono mb-4 max-w-lg break-all">
+              {this.state.error.message}
+            </p>
+          )}
+          <button
+            onClick={this.handleReset}
+            className="flex items-center gap-2 px-4 py-2 bg-white/10 hover:bg-white/20 rounded-lg text-white/80 transition-colors text-sm"
+          >
+            <RefreshCw className="w-4 h-4" />
+            Try again
+          </button>
+        </div>
+      )
+    }
+
+    return this.props.children
+  }
+}