880cfb4ec5
Per-request grammar constraints in serve mode: response_format plumbed through the API, per-request grammar compilation, and grammar-forced draft verification. Verified locally on top of current dev: clean build, token-exact tiny models unchanged, decode-batch helper tests ok, 40/40 openai_server tests. CI 8/8 green. Thanks @fabio-rovai for keeping this rebased through the refactor.