California like most States doesn't allow dairy containing foods unless prepared in a commercial facility and refrigerated as needed. It's technically a slight grey area from a food microbiology position, but nearly all simple dairy + chocolate ganache formulations will have a Water Activity (aW) >0.85 which puts them firmly as 'potentially hazardous foods' (PHF) as described in the Federal and most State food regulations (the later typically adopt the Federal rules as State code)
We chocolatiers often tweak recipes to reduce aW in an effort increase shelf life without adverse effects on favour/texture. Chocolate ganache with an aW <0.7 made in sanitary conditions stored at 12C can last at least 8 weeks or longer, as most spoilage organisms and more importantly pathogenic bacteria don't grow under these conditions.
However, the food safety regulations only consider that at an aW >0.85 both food spoiling microrganisms and any pathogenic bacteria present can and will grow if the product is held at room temp during it's shelf life, providing a significant risk of food born illness. Dairy including fresh milk, cream even if UHT are regarded as high risk components in filled chocolates, hence not allowed in Cottage / home produced products.
Caramel, toffee, dipped marshmallows, dried fruit, nuts, and fondant will have an aW <0.7 or lower as does a typical chocolate bar.... Thus they are considered low(er) risk (non-PHF) and often allowed to be made and sold outside of commercially regulated food production facilities i.e. Cottage / Home producers.
I also note the California home food rule doesn't require liability insurance for producers of 'home foods'. Risky, one bad batch of ganache and a food born illness claim could leave you living in a tent as you have to sell your home to cover the legal bill!
My tips for you:
1. Find a good clean commercial kitchen, you will need a space you can use for production with approved materials, and also store the finished goods there.
2. Get trained / upto speed regarding the food safety aspects and regulation. Review City, County, State rules and if you do any internet sales also the Federal rules as they will also impact your business.
3. Take out a decent liability insurance policy, which is typically needed in any event if you want to sell at farmer's markets or other public events and totally required if you do 'indirect sales' (no retailer or broker will take your produce without this)
Making the stuff is the relatively easy part, turning the hobby or interest into a legal, safe and viable business takes real effort and expertise.