fix(config): enable documentation mode only explicitly

ConfigEOS.documentation_mode() was true as soon as Sphinx was imported
anywhere in the process. A test importing Sphinx therefore switched all
later tests into documentation mode, and test_config_md_current failed
depending on test order. Documentation mode is now enabled only by the
documentation generators (_force_documentation_mode) or by the Sphinx
configuration, which sets sys._called_from_sphinx in docs/conf.py.

Declare _force_documentation_mode as a ClassVar. Without the annotation
pydantic turned it into a private attribute, and the class attribute was
a truthy descriptor object.

Behavior change: because of that descriptor, every running EOS was in
documentation mode, so the get_adapter/config/measurement/prediction/ems/
database/resource_registry() guards never raised "access before init" and
created the singletons lazily on first access. They now raise for every
access before initialization. The worker process of uvicorn's auto-reload
(server.reload, make run-dev) relied on that: the app's lifespan now sets up
the configuration and initializes the singletons that do not exist yet.

Leave runtime state out of the documentation: the Home Assistant entity ID
properties and OptimizationCommonSettings.keys return an empty list in
documentation mode, so entity IDs and solution keys of a running system
no longer reach the generated configuration docs.

Keep the tests isolated: test_doc sets documentation mode on the class
and test_docstringrst restores sys._called_from_sphinx after reading the
Sphinx configuration. Add tests for how documentation mode is enabled and
for the runtime values it leaves out.

Additional changes
- Generate openapi.json in documentation mode, as the config docs.
- Share the documentation mode check as coreabc.documentation_mode().
- Move the logging and server address setup of run_eos() to setup_eos_config().
- Test that EOS starts with server.reload.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_typingmodels.py

@@ -117,6 +117,27 @@ def test_homeassistant_settings_preserve_entity_lookup_and_unavailability(
     assert getattr(settings, property_name) == []
 
 
+@pytest.mark.parametrize(
+    "property_name",
+    ["homeassistant_entity_ids", "eos_solution_entity_ids", "eos_device_instruction_entity_ids"],
+)
+def test_homeassistant_settings_leave_runtime_entities_out_of_documentation(
+    monkeypatch: pytest.MonkeyPatch, property_name: str
+) -> None:
+    """Entity IDs of a running system do not reach the documentation."""
+    provider = HomeAssistantAdapter()
+    lookup = MagicMock(return_value=["sensor.eos_example"])
+    monkeypatch.setattr(HomeAssistantAdapter, f"get_{property_name}", lookup)
+    adapter = MagicMock()
+    adapter.provider_by_id.return_value = provider
+    monkeypatch.setattr(homeassistant, "get_adapter", lambda: adapter)
+    monkeypatch.setattr(ConfigEOS, "_force_documentation_mode", True)
+
+    settings = HomeAssistantAdapterCommonSettings()
+    assert getattr(settings, property_name) == []
+    lookup.assert_not_called()
+
+
 @pytest.mark.parametrize("operation", ["revert_settings", "list_backups"])
 def test_backup_operations_report_an_uninitialized_path_as_an_invariant_failure(
     config_eos: ConfigEOS, monkeypatch: pytest.MonkeyPatch, operation: str