feat: add permission toggle for public sharing of notes

This commit introduces a new permission toggle that allows administrators to control whether users can publicly share their notes.

- Adds a new environment variable `USER_PERMISSIONS_NOTES_ALLOW_PUBLIC_SHARING` to control the default setting.
- Adds a `public_notes` permission to the `sharing` section of the user permissions.
- Adds a toggle switch to the admin panel for managing this permission.
- Implements backend logic to enforce the permission when a user attempts to share a note publicly.

backend/open_webui/config.py

@@ -1217,6 +1217,11 @@ USER_PERMISSIONS_WORKSPACE_MODELS_ALLOW_PUBLIC_SHARING = (
     == "true"
 )
 
+USER_PERMISSIONS_NOTES_ALLOW_PUBLIC_SHARING = (
+    os.environ.get("USER_PERMISSIONS_NOTES_ALLOW_PUBLIC_SHARING", "False").lower()
+    == "true"
+)
+
 USER_PERMISSIONS_WORKSPACE_KNOWLEDGE_ALLOW_PUBLIC_SHARING = (
     os.environ.get(
         "USER_PERMISSIONS_WORKSPACE_KNOWLEDGE_ALLOW_PUBLIC_SHARING", "False"
@@ -1354,6 +1359,7 @@ DEFAULT_USER_PERMISSIONS = {
         "public_knowledge": USER_PERMISSIONS_WORKSPACE_KNOWLEDGE_ALLOW_PUBLIC_SHARING,
         "public_prompts": USER_PERMISSIONS_WORKSPACE_PROMPTS_ALLOW_PUBLIC_SHARING,
         "public_tools": USER_PERMISSIONS_WORKSPACE_TOOLS_ALLOW_PUBLIC_SHARING,
+        "public_notes": USER_PERMISSIONS_NOTES_ALLOW_PUBLIC_SHARING,
     },
     "chat": {
         "controls": USER_PERMISSIONS_CHAT_CONTROLS,