document the Netlify CLI and ignore local build files

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YNHsWYTXPThURz6TbVS1j3

.gitignore

@@ -2,3 +2,7 @@ public
 .DS_Store
 resources
 
+
+# Local Netlify folder
+.netlify
+.hugo_build.lock

README.md

@@ -1,5 +1,14 @@
 # www.itix.fr
 
+## Netlify CLI
+
+```sh
+npm install -g netlify-cli
+netlify login
+netlify link
+netlify status
+```
+
 ## How to update this website
 
 Create a new branch: