feat: 实现文档集管理系统

新增功能：
   - 文档集创建：支持添加 .md/.txt/.v/.sv/.pdf 格式文件
   - 智能限制：单文件 10MB，总容量 50MB，最多 1000 个文件
   - 状态管理：实时显示索引状态（待索引/索引中/已索引）
   - 交互优化：支持文件预览、删除操作，带 loading 动画

   技术实现：
   - 新增 docsetDialog 组件处理文档集对话框
   - 新增 contextSettingsComponent 管理上下文设置
   - 扩展 contextHelper 支持文档集 CRUD 操作
   - 优化 messageRouter 处理文档集相关消息

src/panels/helpers/messageRouter.ts

@@ -32,6 +32,8 @@ import {
   handleAddContextFolder,
   handleAddContextImage,
   handleAddContextDocument,
+  handleAddContextDocumentSet,
+  handleGetDocumentSetList,
 } from "./contextHelper";
 import { openFile, openFileWithSelection, openFilePathTag } from "./fileHelper";
 
@@ -356,6 +358,90 @@ export async function handleWebviewMessage(
       await handleAddContextFolder(panel);
       break;
 
+    case "addContextDocumentSet":
+      await handleAddContextDocumentSet(panel);
+      break;
+
+    case "getDocumentSetList":
+      await handleGetDocumentSetList(panel);
+      break;
+
+    case "saveDocumentSet":
+      const { saveDocumentSet } = await import("./contextHelper");
+      saveDocumentSet(message.documents || []);
+      break;
+
+    case "openContextSettings":
+      panel.webview.postMessage({
+        command: "openSettingsTab",
+        tab: "context"
+      });
+      break;
+
+    case "selectFilesForDocset":
+      const uris = await vscode.window.showOpenDialog({
+        canSelectMany: true,
+        canSelectFiles: true,
+        canSelectFolders: false,
+        openLabel: "选择文件",
+        filters: {
+          "支持的文件": ["md", "txt", "v", "sv", "pdf"],
+        },
+      });
+
+      if (uris && uris.length > 0) {
+        const fs = require("fs");
+        const path = require("path");
+        const selectedFiles: Array<{ path: string; relativePath: string; size: number }> = [];
+        const MAX_FILE_SIZE = 10 * 1024 * 1024; // 10 MB
+        const MAX_TOTAL_SIZE = 50 * 1024 * 1024; // 50 MB
+        const MAX_FILES = 1000;
+        let totalSize = 0;
+        const errors: string[] = [];
+
+        for (const uri of uris) {
+          const filePath = uri.fsPath;
+          const ext = path.extname(filePath).toLowerCase();
+
+          if (![".md", ".txt", ".v", ".sv", ".pdf"].includes(ext)) {
+            errors.push(`文件 ${path.basename(filePath)} 格式不支持`);
+            continue;
+          }
+
+          try {
+            const stat = fs.statSync(filePath);
+            if (stat.size > MAX_FILE_SIZE) {
+              errors.push(`文件 ${path.basename(filePath)} 超过 10 MB`);
+              continue;
+            }
+            if (totalSize + stat.size > MAX_TOTAL_SIZE) {
+              errors.push("文档集总大小超过 50 MB");
+              break;
+            }
+            if (selectedFiles.length >= MAX_FILES) {
+              errors.push("文件数量超过 1000 个");
+              break;
+            }
+
+            selectedFiles.push({
+              path: filePath,
+              relativePath: vscode.workspace.asRelativePath(filePath),
+              size: stat.size,
+            });
+            totalSize += stat.size;
+          } catch (err) {
+            errors.push(`无法读取文件 ${path.basename(filePath)}`);
+          }
+        }
+
+        panel.webview.postMessage({
+          command: "filesSelectedForDocset",
+          files: selectedFiles,
+          errors: errors.length > 0 ? errors : undefined,
+        });
+      }
+      break;
+
     case "addContextImage":
       await handleAddContextImage(panel);
       break;