Every freelance writer, marketer, and consultant who quietly ships Claude text as their own is now one API call away from being checked. Anthropic is releasing a public detection API. Your clients will be able to run your deliverables through it. This isn't just an Anthropic thing. OpenAI, Google, Meta, Microsoft, and Mistral all signed the same EU Code of Practice, around 190 signatories total. Within the transition period, essentially all frontier model text ships watermarked. Switching…