fix(vscode-ide-companion): improve type safety in webview components

修复 webview 组件的类型安全问题：
- App.tsx: 规范化工具调用状态为联合类型
- InProgressToolCall.tsx: 安全处理非字符串类型的 title 属性
- InputForm.tsx: 修正 RefObject 泛型类型声明
- ReadToolCall.tsx: 添加空 children 避免 ToolCallContainer 警告

packages/vscode-ide-companion/src/webview/components/InputForm.tsx

@@ -10,7 +10,9 @@ type EditMode = 'ask' | 'auto' | 'plan';
 
 interface InputFormProps {
   inputText: string;
-  inputFieldRef: React.RefObject<HTMLDivElement | null>;
+  // Note: RefObject<T> carries nullability in its `current` property, so the
+  // generic should be `HTMLDivElement` (not `HTMLDivElement | null`).
+  inputFieldRef: React.RefObject<HTMLDivElement>;
   isStreaming: boolean;
   isComposing: boolean;
   editMode: EditMode;