docs: add lfe-ls link and brew dependencies

README.md

@@ -57,6 +57,9 @@ alias ec='emacsclient -c -a ""'  # GUI
 ```bash
 brew install ag         # silver searcher (for doom)
 brew install just       # command runner
+brew install direnv     # directory-based env vars
+brew install libvterm   # for vterm terminal
+brew install cmake      # for vterm compilation
 ```
 
 ## Prerequisites
@@ -77,6 +80,9 @@ Current location: `~/.local/bin/erlang_ls`
 LFE Language Server - **must be started manually** before opening LFE files.
 
 ```bash
+# Install from source
+# https://github.com/mdbergmann/lfe-ls
+
 # Start the server (listens on localhost:10567)
 lfe-ls
 ```