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

custom_components/houseplan/system_health.py

@@ -0,0 +1,32 @@
+"""System health for House Plan (Settings → System → Repairs → System information)."""
+from __future__ import annotations
+
+from typing import Any
+
+from homeassistant.components import system_health
+from homeassistant.core import HomeAssistant, callback
+
+from .store import get_data
+
+
+@callback
+def async_register(hass: HomeAssistant, register: system_health.SystemHealthRegistration) -> None:
+    """Register the system health info callback."""
+    register.async_register_info(system_health_info)
+
+
+async def system_health_info(hass: HomeAssistant) -> dict[str, Any]:
+    """Return integration health info."""
+    data = get_data(hass)
+    if data is None:
+        return {"status": "not set up"}
+    cfg_raw = await data.config_store.async_load() or {}
+    layout_raw = await data.store.async_load() or {}
+    config = cfg_raw.get("config", {})
+    return {
+        "config_rev": cfg_raw.get("rev", 0),
+        "spaces": len(config.get("spaces", [])),
+        "rooms": sum(len(s.get("rooms", [])) for s in config.get("spaces", [])),
+        "markers": len(config.get("markers", [])),
+        "layout_entries": len(layout_raw.get("layout", {})),
+    }