Add GPU error handling and performance optimizations

Introduces a comprehensive GPU configuration and fallback system to resolve GPU process launch failures (Error 18), including new modules for GPU management and performance monitoring. Adds a GPU diagnostics HTML page, optimized CSS for rendering, and a diagnostic startup script. Updates main and preload scripts for improved stability, async file operations, and enhanced API exposure. Site history and bookmarks handling are optimized for performance and reliability.

performance-monitor.js

@@ -0,0 +1,100 @@
+// performance-monitor.js - Monitor and optimize browser performance
+const { app } = require('electron');
+
+class PerformanceMonitor {
+  constructor() {
+    this.metrics = {
+      memoryUsage: [],
+      cpuUsage: [],
+      loadTimes: []
+    };
+    this.startTime = Date.now();
+  }
+
+  // Monitor memory usage
+  trackMemory() {
+    const usage = process.memoryUsage();
+    this.metrics.memoryUsage.push({
+      timestamp: Date.now(),
+      rss: usage.rss,
+      heapUsed: usage.heapUsed,
+      heapTotal: usage.heapTotal,
+      external: usage.external
+    });
+
+    // Keep only last 100 measurements
+    if (this.metrics.memoryUsage.length > 100) {
+      this.metrics.memoryUsage.shift();
+    }
+  }
+
+  // Monitor CPU usage
+  trackCPU() {
+    const usage = process.cpuUsage();
+    this.metrics.cpuUsage.push({
+      timestamp: Date.now(),
+      user: usage.user,
+      system: usage.system
+    });
+
+    if (this.metrics.cpuUsage.length > 100) {
+      this.metrics.cpuUsage.shift();
+    }
+  }
+
+  // Track page load times
+  trackLoadTime(url, loadTime) {
+    this.metrics.loadTimes.push({
+      timestamp: Date.now(),
+      url,
+      loadTime
+    });
+
+    if (this.metrics.loadTimes.length > 50) {
+      this.metrics.loadTimes.shift();
+    }
+  }
+
+  // Get performance report
+  getReport() {
+    const memAvg = this.metrics.memoryUsage.length > 0 
+      ? this.metrics.memoryUsage.reduce((sum, m) => sum + m.heapUsed, 0) / this.metrics.memoryUsage.length
+      : 0;
+
+    const avgLoadTime = this.metrics.loadTimes.length > 0
+      ? this.metrics.loadTimes.reduce((sum, l) => sum + l.loadTime, 0) / this.metrics.loadTimes.length
+      : 0;
+
+    return {
+      uptime: Date.now() - this.startTime,
+      averageMemoryUsage: Math.round(memAvg / 1024 / 1024), // MB
+      averageLoadTime: Math.round(avgLoadTime),
+      totalPageLoads: this.metrics.loadTimes.length
+    };
+  }
+
+  // Start monitoring
+  start() {
+    // Monitor every 30 seconds
+    setInterval(() => {
+      this.trackMemory();
+      this.trackCPU();
+    }, 30000);
+
+    // Log performance report every 5 minutes
+    setInterval(() => {
+      const report = this.getReport();
+      console.log('Performance Report:', report);
+    }, 5 * 60 * 1000);
+  }
+
+  // Force garbage collection if available
+  forceGC() {
+    if (global.gc) {
+      global.gc();
+      console.log('Forced garbage collection');
+    }
+  }
+}
+
+module.exports = PerformanceMonitor;