feat(core): clone commands and actions when binding runtimes

Add clone support across Action types and Command so commands can be safely
registered or runner-bound without mutating the original instances.

- clone BaseAction implementations across simple, composite, IO, prompt, file,
  HTTP, process, and signal actions
- bind cloned commands in Falyx.add_command_from_command() and CommandRunner
- preserve local never_prompt settings when cloning actions
- rename shared runtime state from options to options_manager for consistency
- seed root and execution option namespaces consistently
- apply scoped root and namespace option overrides during routing and dispatch
- improve namespace completion by delegating option suggestions to FalyxParser
- enrich missing-value errors and error hints

tests/test_falyx/test_signals.py

@@ -0,0 +1,15 @@
+import sys
+
+import pytest
+
+from falyx import Falyx
+
+
+async def test_run_quit_signal_exits_130(monkeypatch):
+    flx = Falyx(default_to_menu=False)
+    monkeypatch.setattr(sys, "argv", ["prog", "X"])
+
+    with pytest.raises(SystemExit) as exc:
+        await flx.run()
+
+    assert exc.value.code == 130