Never tried it for long time , but $system.CSP.Shell() might be a starting point
$system.CSP.*  seems to have some more useful methods.

I see a general problem in interpretation of the "spiral" 
so I took some drawing for aquadratíc and a rectangular matrix. 

1. depending on the starting point you have to take a pre-designed direction
2. if you hit the diagonal you have to turn right
3. you have to invalidate the row/column you just were on
4. proceeding to invalid points is not allowed.
5. start a the central point is an immediate termination as it has no direction to proceed

The diagonal came to my mind thinking how to NOT increase the imaginative radius of the spiral.
The related subscripts for the diagonale points of an n*m are found as (-n/2+x,-m/2+y) 
The pink subscripts are obviously (n/2,m/2) and might be just virtual.   

As subscripts start with 1 and first  piece position  is also 1
some more adjustment of coordinates is required

I haven't written any useful line yet.

DC search; Improve selectivity of Articles and Questions by using TAGS
https://ideas.intersystems.com/ideas/DPI-I-630

The clockwise logic is simple for a  3*3 matrix
though starting with 4*4  there is some rule missing on how the handle a dead end
Starting at a corner (1,1) or similar is trivial. 
BUT:  starting at any other point may create a rathole or miss some boxes 

        Set matrix($Increment(matrix)) = "C,O,D,E"
        Set matrix($Increment(matrix)) = "U,C,H,G"
        Set matrix($Increment(matrix)) = "M,U,F,O"
        Set matrix($Increment(matrix)) = "S,I,F,L"

Start (1,1) is in the example but
Start (1,2) runs ODEGOLFISMU what is the next to (2,1) ?  (1,1)  or (2,2) or ??
worse with Start(2,2) already the first according to description could be
up (1,2) or right (2,3) or left (2,1)  leaving dead ends clockwise.
And this is only with N=4  larger grids may create multiple lost cells.
Clockwise spiral is just not detailed enough for a UNIQUE result to collect ALL cells
A rule how to handle / skip already consumed cells might improve.
Just as I type a non straight spiral solution to (2,2) consuming the full matrix
might be CUISMUCODEGOLFFH
 I fail to imagine grids >5*5
  

2 options:

set mylist = ""
for i = 1:1:5 {
    set item = "item"_i
    set mylist = mylist_$ListBuild(item)
}
zw mylist

kill mylist
for i = 1:1:5 set $li(mylist,i)="item"_i
zw mylist

see docs: https://docs.intersystems.com/ens201813/csp/documatic/%25CSP.Documatic.cls?LIBRARY=%25SYS&CLASSNAME=%25CSP.Response#ContentLength
• property ContentLength as %String;

Sets the Content-Length header. Since the HTTP headers are sent after the OnPreHTTP() method is complete, setting it after this has no effect.

As a first step I would search Journals to find the Globals affected
if they are not in IRISTEMP/CACHETEMP or PPG of if Journal is switched off.

In order to separate routine calls (abc^myroutine) from real ^globals
Though journal just shows Process Ids, no routine names.

Take a look into OpenExchange  there are 669 packages using Docker
Which means at least 90% of them are running on the latest free Community Versions down loaded.
I bet there are enough examples that fit your needs
 

I feel deeply honored and congratulate all other winning contributors!
🌟🌟🌟🌟🌟🌟🌟