fix(dsi): honour the account registration setting

Reject native registration submissions while new accounts are disabled.

hatenadir/ds/v2-xx/sa.py

@@ -39,6 +39,10 @@ class AccountLeaf(resource.Resource):
     def render_POST(self, request):
         if self.action not in {"login.kbd", "register.kbd"}:
             request.setResponseCode(405); return b""
+        if self.action == "register.kbd":
+            from server_config import load_config
+            if not load_config()["registration_enabled"]:
+                return dialog(request, "New account registration is currently closed.")
         value = keyboard_value(request)
         if ":" not in value:
             return dialog(request, "Enter username:password")