refactor(browser): 更新浏览器窗口 HTML 加载方式

- 修复空指针bug：在 BrowserWindow 和 BrowserWindowJDialog 类中初始化 htmlUrl 变量为空字符串

src/main/java/com/axis/innovators/box/browser/BrowserWindow.java

@@ -52,7 +52,7 @@ public class BrowserWindow extends JFrame {
         private boolean resizable = true;       // 默认允许调整大小
         private boolean maximizable = true;     // 默认允许最大化
         private boolean minimizable = true;     // 默认允许最小化
-        private String htmlUrl;
+        private String htmlUrl = "";
 
 
         public Builder resizable(boolean resizable) {

src/main/java/com/axis/innovators/box/browser/BrowserWindowJDialog.java

@@ -53,7 +53,7 @@ public class BrowserWindowJDialog extends JDialog {
         private boolean resizable = true;       // 默认允许调整大小
         private boolean maximizable = true;     // 默认允许最大化
         private boolean minimizable = true;     // 默认允许最小化
-        private String htmlUrl;
+        private String htmlUrl = "";
 
 
         public Builder resizable(boolean resizable) {

src/main/java/com/axis/innovators/box/browser/MainApplication.java

@@ -41,7 +41,7 @@ public class MainApplication {
         WindowRegistry.getInstance().createNewWindow("main", builder ->
                 window.set(builder.title("Axis Innovators Box AI 工具箱")
                         .size(1280, 720)
-                        .htmlUrl("https://chat.deepseek.com/")
+                        .htmlPath("C:\\Users\\Administrator\\Downloads\\deepseek_html_20250817_d94647.html")
                         .operationHandler(createOperationHandler())
                         .build())
         );