#478 feat(fish): add alias for 'jj' to shell aliases

Summary

• Add 'j' alias for 'jj' (Jujutsu) command in Fish shell configuration
• Provides convenient short alias for the Jujutsu version control system

---

Summary by cubic

Add a 'j' alias for Jujutsu in Fish, configure jj (name/email), and install jjui to streamline version control.