fix(webui): drive slash command routing from metadata

tests/command/test_model_command.py

@@ -149,7 +149,10 @@ async def test_model_command_registered_as_exact_and_prefix(tmp_path) -> None:
 def test_model_command_in_help_and_palette() -> None:
     palette = builtin_command_palette()
 
-    assert any(item["command"] == "/model" and item["arg_hint"] == "[preset]" for item in palette)
+    model = next(item for item in palette if item["command"] == "/model")
+    assert model["arg_hint"] == "[preset]"
+    assert model["lifecycle"] == "side_channel"
+    assert model["accepts_args"] is True
     assert "/model [preset]" in build_help_text()
 
 
@@ -204,5 +207,8 @@ async def test_goal_command_registered_on_router(tmp_path) -> None:
 
 def test_goal_command_in_help_and_palette() -> None:
     palette = builtin_command_palette()
-    assert any(item["command"] == "/goal" and item["arg_hint"] == "<goal>" for item in palette)
+    goal = next(item for item in palette if item["command"] == "/goal")
+    assert goal["arg_hint"] == "<goal>"
+    assert goal["lifecycle"] == "agent_turn_with_args"
+    assert goal["accepts_args"] is True
     assert "/goal <goal>" in build_help_text()