feat: harden phase 3 api security

apps/api/exceptions.py

@@ -0,0 +1,13 @@
+from __future__ import annotations
+
+from rest_framework.exceptions import Throttled
+from rest_framework.views import exception_handler
+
+from apps.api.errors import api_error
+
+
+def api_exception_handler(exc, context):
+    response = exception_handler(exc, context)
+    if response is not None and isinstance(exc, Throttled):
+        response.data = api_error("rate_limited", "请求过于频繁，请稍后再试")
+    return response