add NFAA tag (not for all audiences, similar to NSFW)

As there's lots of nudity in the gallery it could be good to have the NFAA tag

README.md

@@ -9,6 +9,8 @@ app_file: app.py
 pinned: true
 license: apache-2.0
 short_description: FLUX, Image to Texto to Image, VLM
+tags:
+  - not-for-all-audiences
 ---
 
 Check out the configuration reference at https://huggingface.co/docs/hub/spaces-config-reference