bat + yazi flavors: sync configs, external the purescript syntax clone

- dot_config/bat: config + cyberdream theme synced; embedded
  sublime-purescript-syntax git clone (with dot_git) replaced by a
  git-repo external (clone-when-missing, ff-only)
- run_onchange bat cache --build hook keyed on theme/config
- yazi cyberdream flavor synced; flavors un-ignored in .chezmoiignore

.chezmoiignore.tmpl

@@ -7,7 +7,6 @@ AGENTS.md
 # Runtime/plugin state living inside managed trees — not managed
 .config/lazygit/.omc/**
 .config/yazi/plugins/**
-.config/yazi/flavors/**
 .config/tmux/plugins/**
 .config/fish/fish_variables
 .config/nvim/lazy-lock.json