feat(core): advance options/state handling and workflow execution integration

- extend OptionsManager to support multi-namespace option resolution and toggling
- integrate OptionsManager more deeply across Action, ChainedAction, and ActionGroup
- propagate shared runtime configuration through execution layers
- refine action composition model (sequential + parallel execution semantics)
- improve lifecycle consistency across BaseAction, Action, ChainedAction, and ActionGroup
- begin aligning execution flow with centralized context and options handling

wip: routing and root option parsing behavior still in progress

tests/test_actions/test_chained_action_empty.py

@@ -0,0 +1,28 @@
+import pytest
+
+from falyx.action import ChainedAction
+from falyx.exceptions import EmptyChainError
+
+
+@pytest.mark.asyncio
+async def test_chained_action_raises_empty_chain_error_when_no_actions():
+    """A ChainedAction with no actions should raise an EmptyChainError immediately."""
+    chain = ChainedAction(name="empty_chain", actions=[])
+
+    with pytest.raises(EmptyChainError) as exc_info:
+        await chain()
+
+    assert "No actions to execute." in str(exc_info.value)
+    assert "empty_chain" in str(exc_info.value)
+
+
+@pytest.mark.asyncio
+async def test_chained_action_raises_empty_chain_error_when_actions_are_none():
+    """A ChainedAction with None as actions should raise an EmptyChainError immediately."""
+    chain = ChainedAction(name="none_chain", actions=None)
+
+    with pytest.raises(EmptyChainError) as exc_info:
+        await chain()
+
+    assert "No actions to execute." in str(exc_info.value)
+    assert "none_chain" in str(exc_info.value)