bashlex (GPL-3+) powers upcoming structural command analysis: parsing
pipelines into segments with word offsets so a typo anywhere in a
command can be fixed as confidently as one at the start. Because the
license is incompatible with distributing the MIT-licensed app, the
dependency is import-guarded: thefuck/shell_ast.py exposes
AST_AVAILABLE, which is False when bashlex is missing or under python 2
(the py2.7 CI requirements.txt deliberately omits it), so all new
behavior must gate on it and the fork stays personal-use only.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>