Integration into QuickFolders for French users

[RealRaven2000]

I would like to be able to remap Shortcuts for my French users, they use Ctrl+Number (without Shift) to activate one of 10 QuickFolders Tabs:

The problem is that it is not possible to type a number without SHIFT on AZERTY keyboards.
they only allow CTRL + & é " ' ( - è _ ç à ) = - numbers require SHIFT.

I see that we can use internal Thunderbird commands in a shortcut, would it be possible to access global name spaced functions in experimental Add-ons as well? I have a global namespace "window.QuickFolders" that could be used. Alternatively, can the shortcuts be remapped to be other shortcuts?

E.g.:

{
    "ctrl+&": "ctrl+1",
    "ctrl+é": "ctrl+2",
    "ctrl+\"": "ctrl+3",
    "ctrl+'": "ctrl+4",
    "ctrl+(": "ctrl+5",
    "ctrl+-": "ctrl+6",
    "ctrl+è": "ctrl+7",
    "ctrl+_": "ctrl+8",
    "ctrl+ç": "ctrl+9",
    "ctrl+à": "ctrl+0",
}

[RealRaven2000]

For testing. I have tried the following:

{
    "ctrl+0": "unset",
    "ctrl+1": "memsg:[email protected]:{cmd:'shortcut',code:1,isCtrl:true}",
    "ctrl+2": "memsg:[email protected]:{cmd:'shortcut',code:2,isCtrl:true}",
}

In my (QuickFolders) background page I have added a switch statement for this one:

  messenger.runtime.onMessage.addListener((data, sender) => {
    if (msg_commands.includes(data.command)) {
      return notificationHandler(data, sender); // the result of this is a Promise
    }
    switch (data.command) {
      case "shortcut":
        console.log("QuickFolders: Received shortcut:", { data , sender });
        break;
    }
  });

obviously I am trying a json object as the "message". not sure how a "string message" would work syntactially? An example would be great!

I also tried:
"ctrl+2": "memsg:[email protected]:'TEST'"
and
"ctrl+2": "memsg:[email protected]:TEST"

but messenger.runtime.onMessage in my Add-on never receives anything. What am I doing wrong? The Add-on id is from my manifest:

  "manifest_version" : 2,
  "applications" : {
    "gecko" : {
      "id" : "[email protected]",
      "strict_min_version" : "111.0",
      "strict_max_version" : "132.*"
    }
  },