#### Description Fish only fires `fish_exit` handlers on a clean shell exit, so a shell killed by SIGHUP/crash (closing a terminal, `tmux kill-server`, etc.) never runs `_tide_on_fish_exit`, leaving its `_tide_prompt_$fish_pid` universal variable behind forever. Sweeps and removes any such uvar whose PID is no longer alive, on every `fisher update`, matching the existing `_tide_migrate_vcs_prompt_items` pattern. #### Motivation and Context Related to #51 and [IlanCosman/tide#636](https://github.com/IlanCosman/tide/issues/636) (upstream). #### How Has This Been Tested - [x] I have tested using **MacOS**. - [ ] I have tested using **Linux**. New littlecheck test (`tests/_tide_migrate_orphaned_prompt_vars.test.fish`) seeding a genuinely-dead PID, the current shell's own live var, a malformed name, and an unrelated var — only the dead one gets erased. Full suite passes. #### Checklist - [ ] I am ready to update the wiki accordingly. - [x] I have updated the tests accordingly. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>