Function read_result_from_untrusted_json 

pub fn read_result_from_untrusted_json(value: &Value) -> ReadResult

Interpret an untrusted JSON-shaped semantic reply from a custom adapter. Unknown shapes become unclassified misses; frame-shaped objects ignore stray miss metadata.

Only "kind": "miss" selects the miss branch. Its reason is parsed from "reason" (unknown strings become unclassified) and its observedWatermarkMs is kept only when it is a JSON number in the timestamp domain. Any other object is frame-shaped: createdAtMs must be a number in the timestamp domain, and a JSON string payload is text while anything else is an empty text payload. The result still needs normalize_read_result for the tracked-key fence rules.