fix(tests): fix remaining 6 failures — mock setup for v3 pipeline

- _get_all_from_vector_store: top_k -> limit (2 missed occurrences)
- test_empty_llm_response_fact_extraction (sync+async): add
  db.get_last_messages mock returning [], set custom_instructions=None,
  fix log assertion to use record.message not record.msg
- test_thinking_tags (sync+async): add embed_batch mock, db mock
  with get_last_messages=[], set custom_instructions=None

Root cause: v3 pipeline calls self.db.get_last_messages() and
self.embedding_model.embed_batch() which weren't mocked, causing
the pipeline to silently fail before reaching the LLM call.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/llms/test_vllm.py

@@ -144,6 +144,7 @@ def create_mocked_memory():
 
         mock_embedder = MagicMock()
         mock_embedder.embed.return_value = [0.1, 0.2, 0.3]
+        mock_embedder.embed_batch.return_value = [[0.1, 0.2, 0.3]]
         mock_embedder_factory.return_value = mock_embedder
 
         mock_vector_store = MagicMock()
@@ -151,9 +152,12 @@ def create_mocked_memory():
         mock_vector_store.add.return_value = None
         mock_vector_factory.return_value = mock_vector_store
 
-        mock_sqlite.return_value = MagicMock()
+        mock_db = MagicMock()
+        mock_db.get_last_messages.return_value = []
+        mock_sqlite.return_value = mock_db
 
         memory = Memory()
+        memory.custom_instructions = None
         memory.api_version = "v1.0"
         return memory, mock_llm, mock_vector_store
 
@@ -170,6 +174,7 @@ def create_mocked_async_memory():
 
         mock_embedder = MagicMock()
         mock_embedder.embed.return_value = [0.1, 0.2, 0.3]
+        mock_embedder.embed_batch.return_value = [[0.1, 0.2, 0.3]]
         mock_embedder_factory.return_value = mock_embedder
 
         mock_vector_store = MagicMock()
@@ -177,9 +182,12 @@ def create_mocked_async_memory():
         mock_vector_store.add.return_value = None
         mock_vector_factory.return_value = mock_vector_store
 
-        mock_sqlite.return_value = MagicMock()
+        mock_db = MagicMock()
+        mock_db.get_last_messages.return_value = []
+        mock_sqlite.return_value = mock_db
 
         memory = AsyncMemory()
+        memory.custom_instructions = None
         memory.api_version = "v1.0"
         return memory, mock_llm, mock_vector_store