B.5.2.0:0 - Kind and publication-form boundary

U.AbductivePrompt is a dependent durable publication-form value under episteme publication and abductive entry, not a root U-kind. Its identity is the typed prompt form that may seed B.5.2 after cue preservation, routing, and language-state threshold checks. A cue, routing note, anomaly sentence, candidate hypothesis, or local prompt label does not become U.AbductivePrompt unless the prompt species, open question, scope, and provenance required by this pattern are present.