⚡️ perf(webview): 降低首屏加载与 WebView2 内存占用

- Monaco Editor 改为首次使用时按需初始化
- AI 面板改为懒加载，延后加载 Markdown 和图表渲染依赖
- 增加 Windows 低内存视觉模式，支持关闭透明 WebView 和 Acrylic
- 补充低内存启动说明与模式解析测试

main.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"context"
+	"os"
+	"strings"
 
 	aiservice "GoNavi-Wails/internal/ai/service"
 	"GoNavi-Wails/internal/app"
@@ -18,6 +20,13 @@ func main() {
 	// Create an instance of the app structure
 	application := app.NewApp()
 	aiService := aiservice.NewService()
+	lowMemoryMode := isLowMemoryMode()
+	backgroundColour := &options.RGBA{R: 0, G: 0, B: 0, A: 0}
+	windowsBackdrop := windows.Acrylic
+	if lowMemoryMode {
+		backgroundColour = &options.RGBA{R: 255, G: 255, B: 255, A: 255}
+		windowsBackdrop = windows.None
+	}
 
 	// Create application with options
 	err := wails.Run(&options.App{
@@ -28,7 +37,7 @@ func main() {
 		AssetServer: &assetserver.Options{
 			Assets: assets,
 		},
-		BackgroundColour: &options.RGBA{R: 0, G: 0, B: 0, A: 0},
+		BackgroundColour: backgroundColour,
 		OnStartup: func(ctx context.Context) {
 			app.InitializeLifecycle(application, ctx)
 			aiservice.InitializeLifecycle(aiService, ctx)
@@ -39,9 +48,9 @@ func main() {
 			aiService,
 		},
 		Windows: &windows.Options{
-			WebviewIsTransparent:              true,
-			WindowIsTranslucent:               true,
-			BackdropType:                      windows.Acrylic,
+			WebviewIsTransparent:              !lowMemoryMode,
+			WindowIsTranslucent:               !lowMemoryMode,
+			BackdropType:                      windowsBackdrop,
 			DisableWindowIcon:                 false,
 			DisableFramelessWindowDecorations: false,
 			WebviewUserDataPath:               resolveWindowsWebviewUserDataPath(),
@@ -56,3 +65,12 @@ func main() {
 		logger.Error(err, "应用启动失败")
 	}
 }
+
+func isLowMemoryMode() bool {
+	switch strings.ToLower(strings.TrimSpace(os.Getenv("GONAVI_LOW_MEMORY_MODE"))) {
+	case "1", "true", "yes", "on":
+		return true
+	default:
+		return false
+	}
+}