* fix(mtproto): synchronize child-process state
Use lifecycle snapshots around the mtg command, completion signal, and exit error so Wait cannot race status and shutdown reads.
* test(mtproto): cover concurrent process exit
* test(mtproto): cover lifecycle field synchronization
---------
Co-authored-by: PathGao <gaoyanbo@gaoyanbodeMacBook-Air.local>
PathGao