feat(backend): add one-time Redis tickets for miniprogram webview login.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_mp_webview_ticket.py

@@ -0,0 +1,46 @@
+import json
+from unittest.mock import patch
+
+import pytest
+
+from app.services import mp_webview_ticket as svc
+
+
+class FakeRedis:
+    def __init__(self):
+        self.data = {}
+
+    def set(self, key, value, ex=None, nx=False):
+        if nx and key in self.data:
+            return False
+        self.data[key] = value
+        return True
+
+    def get(self, key):
+        return self.data.get(key)
+
+    def delete(self, key):
+        return 1 if self.data.pop(key, None) is not None else 0
+
+
+def test_issue_and_consume_once():
+    fake = FakeRedis()
+    with patch.object(svc, "get_sync_redis_client", return_value=fake):
+        ticket = svc.issue_ticket("u1", "sid-1", "rj-1")
+        payload = svc.consume_ticket(ticket)
+        assert payload["userId"] == "u1"
+        assert payload["sessionId"] == "sid-1"
+        assert payload["refreshJti"] == "rj-1"
+        assert svc.consume_ticket(ticket) is None
+
+
+def test_consume_unknown_returns_none():
+    fake = FakeRedis()
+    with patch.object(svc, "get_sync_redis_client", return_value=fake):
+        assert svc.consume_ticket("missing") is None
+
+
+def test_issue_without_redis_raises():
+    with patch.object(svc, "get_sync_redis_client", return_value=None):
+        with pytest.raises(RuntimeError, match="Redis"):
+            svc.issue_ticket("u1", "sid-1")