test(config-flow): drive the menus, pin the tables, probe real HA

The flow tests drove `async_step_init` as if it were the one form, so they
had to learn the menu: a shared helper picks the sub-screen that owns a
payload's keys out of the flow's own `menu_options` (no test re-implements
the routing), and a `save=True` flag walks to "Save and close" so the
assertions read as they did before.

New coverage for this task:

- the menu offers every sub-screen and every row has a handler named
  after it, with the rendered step_id equal to the row id (the invariant
  real HA enforces and the first draft broke);
- edits on one sub-screen are not lost by another, and a page that is
  never saved never writes the entry;
- the apps table: add / edit / remove a row, the icon column round-trips,
  the empty state renders without data, a blank field clears the map, and
  the suggested value is TEXT (the `[object Object]` layer);
- a receiver the selector offers `switch` for, stored and pre-filled;
- the setup menu's rows, their handlers and a connection+receiver merge.

tests/test_config_flow_real_ha.py is new and is the empirical half: it
drives the real `FlowManager`, real probatio validation and the real
frontend serialiser (`to_field_list` + `cv.custom_serializer`) — the call
the HTTP flow view makes — so the menu dispatch, the cleared-selector
shapes and the wire serialisation are established rather than assumed.
It skips when homeassistant is absent; CI runs it with:

    uvx --with homeassistant --with adb-shell pytest tests/test_config_flow_real_ha.py

53 of the stub tests and 11 of the real-HA ones fail on the pre-fix tree.

tests/entity_stublib.py

@@ -67,9 +67,18 @@ def install_selector_faces(selector_module) -> None:
     installers in the flow tests), so the stubs cannot drift apart.
     """
     selector_module.EntitySelector = EntitySelectorStub
-    selector_module.EntitySelectorConfig = lambda *args, **kwargs: ""
+
+    class _Config(types.SimpleNamespace):
+        """Selector configs keep their kwargs (real HA stores them as fields).
+
+        The stub needs them inspectable: which domains a selector offers is a
+        user-visible contract (t56 — the Receiver field accepts a switch), and a
+        lambda throwing the value away cannot pin it.
+        """
+
+    selector_module.EntitySelectorConfig = _Config
     selector_module.SelectSelector = lambda *args, **kwargs: None
-    selector_module.SelectSelectorConfig = lambda **kwargs: ""
+    selector_module.SelectSelectorConfig = _Config
     selector_module.SelectSelectorMode = types.SimpleNamespace(DROPDOWN="dropdown")