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/manifest.json

@@ -15,5 +15,6 @@
   "iot_class": "local_push",
   "issue_tracker": "https://github.com/Matysh/houseplan-card/issues",
   "requirements": [],
-  "version": "1.11.2"
-}
+  "single_config_entry": true,
+  "version": "1.12.0"
+}