NC does not load from composer refactor

[timur-g]

NC 31.0.0 RC4 installed in Ubuntu 22.04.
NC does not load from source richdocuments commit 1e95751 and #4430. Seen with bisect, previous commit works.
GUI shows "Internal Server Error" and the log says:

 "version": "31.0.0.15",
  "exception": {
    "Exception": "Error",
    "Message": "Failed opening required '/var/www/nc/apps/richdocuments/composer/../vendor/autoload.php' (include_path='/var/www/nc/3rdparty/pear/archive_tar:/var/www/nc/3rdparty/pear/console_getopt:/var/www/nc/3rdparty/pear/pear-core-minimal/src:/var/www/nc/3rdparty/pear/pear_exception:/var/www/nc/apps')",
    "Code": 0,
    "Trace": [

@elzody please see.

[timur-g]

Install composer.