Repair lexer ownership when copying LALR interactive parser state and produce a verified branch-isolation…

Repair lexer ownership when copying LALR interactive parser state and produce a verified branch-isolation…: a task in MiMo-V2.6-RL-harbor-terminal: MiMo-V2.6-RL Terminal (Harbor) (Harbor dataset). The vendored project in /app/vendor/lark is a pre-fix production source tree. An incremental LALR…