refactor: 优化 ICHelperPanel 组件结构

- 将 1346 行的单文件拆分为 7 个职责单一的模块
   - authHelper: 认证和登录检查
   - userInfoHelper: 用户信息管理
   - conversationHelper: 会话历史加载
   - vcdHelper: VCD 文件处理
   - contextHelper: 上下文管理
   - fileHelper: 文件操作
   - messageRouter: 消息路由分发
   - 主组件精简至 157 行，提升可维护性

src/panels/helpers/contextHelper.ts

@@ -0,0 +1,104 @@
+/**
+ * 上下文管理模块
+ * 功能：处理文件、文件夹、图片、文档上下文添加
+ * 依赖：vscode, fs, path
+ * 使用场景：用户添加上下文项时
+ */
+import * as vscode from "vscode";
+
+export async function handleAddContextFile(panel: vscode.WebviewPanel) {
+  const workspaceFolder = vscode.workspace.workspaceFolders?.[0];
+  if (!workspaceFolder) {
+    vscode.window.showWarningMessage("请先打开一个工作区");
+    return;
+  }
+
+  const files = await vscode.workspace.findFiles(
+    "**/*",
+    "**/node_modules/**",
+  );
+
+  panel.webview.postMessage({
+    command: "showWorkspaceFileList",
+    files: files.map((uri) => ({
+      path: uri.fsPath,
+      relativePath: vscode.workspace.asRelativePath(uri),
+    })),
+  });
+}
+
+export async function handleAddContextFolder(panel: vscode.WebviewPanel) {
+  const workspaceFolder = vscode.workspace.workspaceFolders?.[0];
+  if (!workspaceFolder) {
+    vscode.window.showWarningMessage("请先打开一个工作区");
+    return;
+  }
+
+  const fs = require("fs");
+  const path = require("path");
+  const folders: Array<{ path: string; relativePath: string }> = [];
+
+  function scanFolders(dir: string, baseDir: string) {
+    try {
+      const items = fs.readdirSync(dir, { withFileTypes: true });
+      for (const item of items) {
+        if (
+          item.isDirectory() &&
+          item.name !== "node_modules" &&
+          !item.name.startsWith(".")
+        ) {
+          const fullPath = path.join(dir, item.name);
+          const relativePath = path.relative(baseDir, fullPath);
+          folders.push({ path: fullPath, relativePath });
+          scanFolders(fullPath, baseDir);
+        }
+      }
+    } catch (error) {
+      console.error("扫描文件夹失败:", error);
+    }
+  }
+
+  scanFolders(workspaceFolder.uri.fsPath, workspaceFolder.uri.fsPath);
+
+  panel.webview.postMessage({
+    command: "showWorkspaceFolderList",
+    folders: folders,
+  });
+}
+
+export async function handleAddContextImage(panel: vscode.WebviewPanel) {
+  const imageUris = await vscode.window.showOpenDialog({
+    canSelectFiles: true,
+    canSelectFolders: false,
+    canSelectMany: true,
+    openLabel: "选择图片",
+    filters: {
+      图片文件: ["png", "jpg", "jpeg", "gif", "bmp", "svg", "webp"],
+    },
+  });
+  if (imageUris && imageUris.length > 0) {
+    panel.webview.postMessage({
+      command: "contextImagesSelected",
+      images: imageUris.map((uri) => uri.fsPath),
+    });
+  }
+}
+
+export async function handleAddContextDocument(panel: vscode.WebviewPanel) {
+  const docUris = await vscode.window.showOpenDialog({
+    canSelectFiles: true,
+    canSelectFolders: false,
+    canSelectMany: true,
+    openLabel: "选择文档",
+    filters: {
+      文档文件: ["pdf", "doc", "docx", "txt", "md"],
+      所有文件: ["*"],
+    },
+  });
+  if (docUris && docUris.length > 0) {
+    panel.webview.postMessage({
+      command: "contextDocumentsSelected",
+      documents: docUris.map((uri) => uri.fsPath),
+    });
+  }
+}