fix(mcp): initialize task manager so async fs operations don't panic

cmd/mcp.go (added in v3.60.0) calls Init() and LoadStorages() but skips
bootstrap.InitTaskManager(). As a result fs.CopyTaskManager,
fs.UploadTaskManager, fs.MoveTaskManager and friends are nil, and any
MCP fs_copy / fs_move on a cross-storage target panics at
internal/fs/copy.go (CopyTaskManager.Add) with a nil-pointer dereference
that the MCP handler surfaces as:

    panic recovered in fs_copy tool handler:
    runtime error: invalid memory address or nil pointer dereference

Mirror the cmd/server.go bootstrap order so the MCP command initializes
the task manager too.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: okatu-loli

cmd/mcp.go

@@ -14,6 +14,7 @@ var MCPCmd = &cobra.Command{
 	Run: func(cmd *cobra.Command, args []string) {
 		Init()
 		bootstrap.LoadStorages()
+		bootstrap.InitTaskManager()
 		username, _ := cmd.Flags().GetString("user")
 		if err := mcpserver.ServeStdio(username); err != nil {
 			utils.Log.Fatalf("MCP STDIO server error: %v", err)