Add clean target to Makefile for migration from old stow structure

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Makefile

@@ -1,7 +1,14 @@
-.PHONY: laptop work
+.PHONY: laptop work clean
 
 laptop:
 	stow shared laptop
 
 work:
 	stow shared work
+
+clean:
+	stow -D shared laptop work 2>/dev/null; \
+	find $(HOME)/.config/nvim $(HOME)/.config/emacs $(HOME)/.config/tmux \
+	     $(HOME)/.config/ghostty $(HOME)/.config/ranger \
+	     -maxdepth 4 -xtype l -delete 2>/dev/null; \
+	true