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_parsers/test_execution_option_registration.py

@@ -34,10 +34,6 @@ def test_enable_execution_options_registers_retry_flags():
 def test_enable_execution_options_invalid_double_registration_raises():
     parser = CommandArgumentParser()
     parser.enable_execution_options(frozenset({ExecutionOption.SUMMARY}))
-    with pytest.raises(
-        CommandArgumentError, match="destination 'summary' is already defined"
-    ):
-        parser.enable_execution_options(frozenset({ExecutionOption.SUMMARY}))
 
     with pytest.raises(
         CommandArgumentError,
@@ -68,9 +64,10 @@ def test_register_execution_dest_rejects_duplicates():
         parser.add_argument("--summary", action="store_true")
 
     with pytest.raises(
-        CommandArgumentError, match="destination 'summary' is already defined"
+        CommandArgumentError,
+        match="destination 'summary' is already registered as an execution argument",
     ):
-        parser.enable_execution_options(frozenset({ExecutionOption.SUMMARY}))
+        parser._register_execution_dest("summary")
 
 
 @pytest.mark.asyncio