Move fixed copy into the difyBuilder i18n namespace and resolve scene IDs
using reply_language. Preserve dynamic streaming, historical receipts,
and submitted values.
Show fixed replies immediately with a short transition, detect language
before initial progress, and retire new notices and recovery messages.
Keep recovery and publication validation in place.
Update generated contracts and regression coverage, including progress
snapshot and execution context expectations and test type annotations.
Charles Yao
twwu