Replace hardcoded config/environment.d/generic.conf with a Tera
template (environments.tmpl) rendered via mise, pulling DOTFILES_DIR,
THEME_DIR, SECOND_BRAIN, and user info from mise.toml vars.
- Add SECOND_BRAIN variable in mise.toml for the vault path
- Update fish aliases to use $SECOND_BRAIN instead of a hardcoded path
- Fix Obsidian nvim aliases with proper quoting
- Remove stale dotfiles.conf template reference
gitadmin