I found that issue posted by me is a duplicate of this one: Empty vector menu in QGIS 3.0.0 . Mentioned ticked includes solution. As far as i know this bug still occures. Additional solutions may be find here: https://issues.qgis.org/issues/18202 .
Most definitely there is an End Of Line issue in the CSV file.
I would guess QGIS is on a Windows machine, and the CSV only has Carriage Retruns (CR) or linefeeds (LF), while it need both (CR+LF, or 0x0A + 0x0D).
A simple fix is to convert all line breaks of the CSV file into CR+LF.
Luckily it is an easy operation, and there are tons of options:
Good question. It is not obvious, but you need to copy your script algorithms to a specific folder to make your standalone script able to run them.
You can easily see where your script algorithms should be located by adding a couple of lines to your standalone script:
from processing.script import ScriptUtils
print("Folder for script algorithms:", ...