refactor(agent): capture runtime at turn admission

tests/agent/test_loop_runner_integration.py

@@ -40,7 +40,9 @@ async def test_loop_max_iterations_message_stays_stable(tmp_path):
     loop.tools.execute = AsyncMock(return_value="ok")
     loop.max_iterations = 2
 
-    final_content, _, _, _, _ = await loop._run_agent_loop([])
+    final_content, _, _, _, _ = await loop._run_agent_loop(
+        [], runtime=loop.llm_runtime()
+    )
 
     assert final_content == (
         "I reached the maximum number of tool call iterations (2) "
@@ -61,6 +63,7 @@ async def test_loop_goal_turn_uses_standard_iteration_budget(tmp_path):
 
     final_content, _, _, stop_reason, _ = await loop._run_agent_loop(
         [],
+        runtime=loop.llm_runtime(),
         metadata={"original_command": "/goal"},
     )
 
@@ -94,6 +97,7 @@ async def test_loop_stream_filter_handles_think_only_prefix_without_crashing(tmp
 
     final_content, _, _, _, _ = await loop._run_agent_loop(
         [],
+        runtime=loop.llm_runtime(),
         on_stream=on_stream,
         on_stream_end=on_stream_end,
     )
@@ -118,7 +122,9 @@ async def test_loop_stream_filter_hides_partial_trailing_think_prefix(tmp_path):
     async def on_stream(delta: str) -> None:
         deltas.append(delta)
 
-    final_content, _, _, _, _ = await loop._run_agent_loop([], on_stream=on_stream)
+    final_content, _, _, _, _ = await loop._run_agent_loop(
+        [], runtime=loop.llm_runtime(), on_stream=on_stream
+    )
 
     assert final_content == "Hello World"
     assert deltas == ["Hello", " World"]
@@ -139,7 +145,9 @@ async def test_loop_stream_filter_hides_complete_trailing_think_tag(tmp_path):
     async def on_stream(delta: str) -> None:
         deltas.append(delta)
 
-    final_content, _, _, _, _ = await loop._run_agent_loop([], on_stream=on_stream)
+    final_content, _, _, _, _ = await loop._run_agent_loop(
+        [], runtime=loop.llm_runtime(), on_stream=on_stream
+    )
 
     assert final_content == "Hello World"
     assert deltas == ["Hello", " World"]
@@ -158,7 +166,9 @@ async def test_loop_retries_think_only_final_response(tmp_path):
 
     loop.provider.chat_with_retry = chat_with_retry
 
-    final_content, _, _, _, _ = await loop._run_agent_loop([])
+    final_content, _, _, _, _ = await loop._run_agent_loop(
+        [], runtime=loop.llm_runtime()
+    )
 
     assert final_content == "Recovered answer"
     assert call_count["n"] == 2