text.md: add LLM inference service section with three-path decision
table (GGUF/transformers/VLM mmproj/classifier), multimodal content-
block API, mock mode, CF_TEXT_URL wiring.
video.md: new file covering Marlin-2B service, server-local video_path
callout, CUDA 13 nightly path, trust_remote_code note, MIT/BSL boundary
(current wrapper is MIT; special sauce pipelines go in separate BSL
module, not cf-core).
mqtt.md: new file covering broker vs serial decision tree, MQTTClient
usage, TopicRouter.matches() NotImplementedError with workaround, install
extras.
