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_dispatch_contract.py

@@ -0,0 +1,120 @@
+import pytest
+
+from falyx import Falyx
+from falyx.routing import RouteKind, RouteResult
+
+
+@pytest.mark.asyncio
+async def test_dispatch_seeds_namespace_defaults_into_default_namespace(
+    monkeypatch,
+):
+    flx = Falyx(program="falyx")
+    command = flx.add_command("D", "Deploy", action=lambda: "ok", aliases=["deploy"])
+
+    route = RouteResult(
+        kind=RouteKind.COMMAND,
+        namespace=flx,
+        context=flx.get_current_invocation_context(),
+        command=command,
+        namespace_defaults={"region": "us-east"},
+        namespace_overrides={},
+    )
+
+    seen = {}
+
+    async def fake_execute(*, command, args, kwargs, execution_args, **_):
+        seen["region"] = flx.options_manager.get("region", None, "default")
+        return "ok"
+
+    monkeypatch.setattr(flx._executor, "execute", fake_execute)
+
+    result = await flx._dispatch_route(
+        route=route,
+        args=(),
+        kwargs={},
+        execution_args={},
+    )
+
+    assert result == "ok"
+    assert seen["region"] == "us-east"
+
+    assert flx.options_manager.get("region", None, "default") == "us-east"
+
+
+@pytest.mark.asyncio
+async def test_dispatch_applies_namespace_overrides_temporarily_in_default_namespace(
+    monkeypatch,
+):
+    flx = Falyx(program="falyx")
+    command = flx.add_command("D", "Deploy", action=lambda: "ok", aliases=["deploy"])
+
+    flx.options_manager.set("region", "us-east", "default")
+
+    route = RouteResult(
+        kind=RouteKind.COMMAND,
+        namespace=flx,
+        context=flx.get_current_invocation_context(),
+        command=command,
+        namespace_defaults={},
+        namespace_overrides={"region": "us-west"},
+    )
+
+    seen = {}
+
+    async def fake_execute(*, command, args, kwargs, execution_args, **_):
+        seen["region"] = flx.options_manager.get("region", None, "default")
+        return "ok"
+
+    monkeypatch.setattr(flx._executor, "execute", fake_execute)
+
+    result = await flx._dispatch_route(
+        route=route,
+        args=(),
+        kwargs={},
+        execution_args={},
+        raise_on_error=False,
+        wrap_errors=True,
+    )
+
+    assert result == "ok"
+    assert seen["region"] == "us-west"
+
+    assert flx.options_manager.get("region", None, "default") == "us-east"
+
+
+@pytest.mark.asyncio
+async def test_namespace_overrides_do_not_leak_after_command_execution(monkeypatch):
+    flx = Falyx(program="falyx")
+    command = flx.add_command("D", "Deploy", action=lambda: "ok", aliases=["deploy"])
+
+    flx.options_manager.set("profile", "dev", "default")
+
+    route = RouteResult(
+        kind=RouteKind.COMMAND,
+        namespace=flx,
+        context=flx.get_current_invocation_context(),
+        command=command,
+        namespace_defaults={"region": "us-east"},
+        namespace_overrides={"profile": "prod"},
+    )
+
+    async def fake_execute(*, command, args, kwargs, execution_args, **_):
+        assert flx.options_manager.get("region", None, "default") == "us-east"
+        assert flx.options_manager.get("profile", None, "default") == "prod"
+        return "ok"
+
+    monkeypatch.setattr(flx._executor, "execute", fake_execute)
+
+    result = await flx._dispatch_route(
+        route=route,
+        args=(),
+        kwargs={},
+        execution_args={},
+        raise_on_error=False,
+        wrap_errors=True,
+    )
+
+    assert result == "ok"
+
+    assert flx.options_manager.get("region", None, "default") == "us-east"
+    assert flx.options_manager.get("profile", None, "default") == "dev"