Update requirements.txt and rename test for pending approval behavior

- Replace hard graphqlite/pysqlite3 deps in requirements.txt with
  comments directing users to optional extras install
- Rename test to reflect that destructive decisions now return
  pending_approval instead of being immediately blocked

Author: johnteee

requirements.txt

@@ -1,2 +1,7 @@
-graphqlite>=0.4.4
-pysqlite3>=0.6.0
+# Core TeaAgent (no mandatory pip dependencies beyond stdlib).
+#
+# To enable Graph RAG features:
+#   pip install -e ".[graphqlite]"
+#
+# For development and testing:
+#   pip install -e ".[dev]"

tests/test_chat_agent.py

@@ -82,7 +82,7 @@ def test_chat_agent_injects_matching_memories_into_prompt(self) -> None:
             self.assertEqual(result.status, "completed")
             self.assertIn("ambiguity gate", adapter.requests[0].messages[0].content)
 
-    def test_destructive_decision_is_blocked_by_default(self) -> None:
+    def test_destructive_decision_returns_pending_approval_by_default(self) -> None:
         with tempfile.TemporaryDirectory() as tmp:
             adapter = FakeAdapter(
                 [