feat v1.12.0: Quality Scale conformance (phases 7-8)

- entry.runtime_data (HouseplanData in store.py) instead of hass.data; WS answers
  not_ready without a loaded entry
- test-before-setup (ConfigEntryNotReady), async_unload_entry, async_remove_entry
  (Lovelace resource cleanup), single_config_entry in manifest
- Store minor_version + migration hook; diagnostics.py (redacted); repairs
  (broken_plan issues, en/ru); system_health.py; strings.json
- quality_scale.yaml self-assessment; HA-harness tests (config flow, WS, upload)
  in CI on py3.13; CI backend job updated

tests_backend/test_ha_config_flow.py

@@ -0,0 +1,50 @@
+"""Config flow tests (run in CI with pytest-homeassistant-custom-component)."""
+from homeassistant import config_entries
+from homeassistant.core import HomeAssistant
+from homeassistant.data_entry_flow import FlowResultType
+
+from custom_components.houseplan.const import CONF_ADMIN_ONLY, DOMAIN
+
+
+async def test_user_flow_creates_entry(hass: HomeAssistant) -> None:
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] is FlowResultType.FORM
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"], user_input={CONF_ADMIN_ONLY: True}
+    )
+    assert result["type"] is FlowResultType.CREATE_ENTRY
+    assert result["title"] == "House Plan"
+    assert result["options"] == {CONF_ADMIN_ONLY: True}
+
+
+async def test_single_instance(hass: HomeAssistant) -> None:
+    """manifest single_config_entry must prevent a second entry."""
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    await hass.config_entries.flow.async_configure(result["flow_id"], user_input={})
+    result2 = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result2["type"] is FlowResultType.ABORT
+    assert result2["reason"] == "single_instance_allowed"
+
+
+async def test_options_flow(hass: HomeAssistant) -> None:
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    result = await hass.config_entries.flow.async_configure(result["flow_id"], user_input={})
+    entry = hass.config_entries.async_entries(DOMAIN)[0]
+    await hass.config_entries.async_setup(entry.entry_id)
+    await hass.async_block_till_done()
+
+    result = await hass.config_entries.options.async_init(entry.entry_id)
+    assert result["type"] is FlowResultType.FORM
+    result = await hass.config_entries.options.async_configure(
+        result["flow_id"], user_input={CONF_ADMIN_ONLY: True}
+    )
+    assert result["type"] is FlowResultType.CREATE_ENTRY
+    assert entry.options == {CONF_ADMIN_ONLY: True}