refactor(agent): remove loop iteration state (#5549)

* refactor(agent): remove loop iteration state

* docs(my): remove stale iteration guidance

tests/agent/tools/test_runtime_control.py

@@ -57,7 +57,22 @@ def test_runtime_snapshot_has_exact_allowlist_and_redacts_secrets(tmp_path: Path
     snapshot = _my_tool(loop)._runtime_control.snapshot()
     values = snapshot.as_mapping()
 
-    assert frozenset(values) == RUNTIME_SNAPSHOT_KEYS
+    expected_snapshot_keys = frozenset({
+        "model",
+        "model_preset",
+        "model_presets",
+        "max_iterations",
+        "context_window_tokens",
+        "workspace",
+        "provider_retry_mode",
+        "max_tool_result_chars",
+        "tool_names",
+        "web_config",
+        "exec_config",
+        "subagents",
+    })
+    assert RUNTIME_SNAPSHOT_KEYS == expected_snapshot_keys
+    assert frozenset(values) == expected_snapshot_keys
     assert RUNTIME_COMMAND_KEYS == frozenset({
         "model",
         "model_preset",