I am working at an organisation that helps young adults/adolescents who receive income supplement/welfare by providing them with a job at said organisation for a period of 3 or 6 months, after which they can (hopefully) find a regular job or go back to school. If translated literally, it would be learning-working company, but I don't know if it would be called learning company or is there a special word for such an organisation?
When this sort of thing is offered to a job seeker through the job centre, it is called a work placement, but there isn't a word for the company, it's just 'this company is offering work placements'.
You could use the phrase stepping stone:
a circumstance that assists progress towards some goal (source)
The company can be seen as a stepping stone for young adults towards a better job.
As the definition shows, this phrase can also be used in many other contexts.