feat(mcp): cache with one-click toggle (#1269)

* feat: enable cache in mcp

* refactor: remove redundant setting

* fix: conflicts during installation

---------

Co-authored-by: Linlang <Lv.Linlang@hotmail.com>

test/oai/test_prefect_cache.py

@@ -0,0 +1,54 @@
+import time
+import unittest
+
+from rdagent.components.agent.context7 import Agent
+
+
+class PydanticTest(unittest.TestCase):
+    """
+    Test Pydantic-AI agent with Prefect caching
+
+    How it works:
+    1. Agent wraps query() with @task(cache_policy=INPUTS) when enable_cache=True
+    2. First call: executes and caches to Prefect server
+    3. Second call with same input: instant cache hit
+    """
+
+    def test_context7_cache(self):
+        """Test that caching works correctly"""
+        query = "pandas read_csv encoding error"
+
+        print("\n" + "=" * 80)
+        print("Testing @task-based caching...")
+        print("=" * 80 + "\n")
+
+        # Create agent once - caching enabled by CONTEXT7_ENABLE_CACHE
+        agent = Agent()
+
+        # First query - will execute and cache
+        print("First query (will execute):")
+        start1 = time.time()
+        res1 = agent.query(query)
+        time1 = time.time() - start1
+
+        print(f"  Time: {time1:.2f}s")
+        print(f"  Length: {len(res1)} chars")
+        print(f"  Preview: {res1[:100]}...\n")
+
+        # Second query - should hit cache (much faster)
+        print("Second query (should hit cache):")
+        start2 = time.time()
+        res2 = agent.query(query)
+        time2 = time.time() - start2
+
+        print(f"  Time: {time2:.2f}s")
+        print(f"  Speedup: {time1/time2:.1f}x faster")
+        print(f"{'='*80}\n")
+
+        self.assertIsNotNone(res1)
+        self.assertGreater(len(res1), 0)
+        self.assertEqual(res1, res2, "Cache must return identical result")
+
+
+if __name__ == "__main__":
+    unittest.main()