minor change in description of Build from source in README.md (#149)

Separated the `node ./dist/cli.js --help ` and `node ./dist/cli.js `.
The comment suggested `node ./dist/cli.js --help ` was to run the
locally-built CLI but in fact it shows the usage an options. It is a
minor change and clarifies the flow for new developers.

README.md

@@ -228,9 +228,12 @@ cd codex/codex-cli
 npm install
 npm run build
 
-# Run the locally‑built CLI directly
+# Get the usage and the options
 node ./dist/cli.js --help
 
+# Run the locally‑built CLI directly
+node ./dist/cli.js
+
 # Or link the command globally for convenience
 npm link
 ```