feat(nix): nix and back again

I tried Nix, but it had too many downsides so I removed it.

1. Didn't like that all files are immutable and simple config changes
need a complete rebuild.
2. Setting up a new Mac didn't work as smoothly as promised. Not worth
the effort.
3. It sucked a lot to always have to type in the password twice on each
darwin-rebuild
4. It solves problems I never had.

.functions/fcdh.sh

@@ -0,0 +1,22 @@
+# fhcd – Jump to home directory and search for directories
+
+fhcd() {
+    # Change to home directory
+    cd "$HOME" || return
+
+    # Change to subdirectory if provided
+    if [ -n "$1" ] && [ -d "$1" ]; then
+        cd "$1" || return
+    fi
+
+    # Find directories and use fzf for selection
+    local dir
+    dir=$(find . -type d | sed '1d; s|^\./||' | fzf --preview 'tree -C {} | head -50')
+
+    # Change to selected directory if one was chosen
+    if [ -n "$dir" ]; then
+        cd "$dir" || return
+    else
+        echo "No directory selected. Staying in current directory."
+    fi
+}