[SETUP] Remove defunct vim subtree and stale subtree metadata

The vim/ subtree had no tracked files or directory and its setup loops
were dead. The tmux/zsh subtrees have not been synced upstream since 2017; all
changes are now direct commits. Delete .gittrees and the vim example-linking
loops.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gittrees

@@ -1,14 +0,0 @@
-[subtree "tmux"]
-url = git@vcs.murgi.de:dotfiles_fabian/tmux.git
-path = tmux
-branch = master
-
-[subtree "zsh"]
-url = git@vcs.murgi.de:dotfiles_fabian/zsh.git
-path = zsh
-branch = master
-
-[subtree "vim"]
-url = git@vcs.murgi.de:dotfiles_fabian/vim.git
-path = vim
-branch = master

setup_arch.sh

@@ -28,7 +28,4 @@ for filename in tmux/.*_arch.example; do
     cp $filename ${filename:0:-13}
 done
 
-for filename in vim/.*_arch.example; do
-    cp $filename ${filename:0:-13}
-done
 echo "You should now start tmux (and zsh) and nvim  for automatic plugin installation."

setup_mac.sh

@@ -26,10 +26,6 @@ for filename in tmux/.*_mac.example(N); do
     gln -Tsvf $PWD/$filename $PWD/${filename:0:-12}
 done
 
-for filename in vim/.*_mac.example(N); do
-    gln -Tsvf $PWD/$filename $PWD/${filename:0:-12}
-done
-
 open fonts/*.ttf
 
 echo "You should now start tmux (and zsh) and nvim for automatic plugin installation."