Do the violet, green and black jacket colours have a standard meaning?

Not universally. In this particular range, violet identifies the indoor LSZH Eca products, green identifies the indoor LSZH Cca products, and black identifies the external PE Fca products.

That is useful shorthand when looking at these products, but jacket colour is not a standards oracle. With another manufacturer or installation, read the actual category, sheath and CPR markings rather than trying to divine the specification from the colour alone.