Add HCHO / VOC air-quality sensors (T9 module)

Support the WSLink t9 air-quality module:
  - t9hcho (formaldehyde, ppb),
  - t9voclv (VOC level 1-5 -> ENUM state)
  - t9bat (0-5 battery -> percentage).

  The t9hcho/t9voclv/t9bat values are dropped when
  t9cn reports the module as disconnected,
  so no empty entities are created.

  - const: HCHO/VOC/T9_BATTERY keys, VOCLevel enum +
  VOC_LEVEL_MAP, BATTERY_NON_BINARY, CONNECTION_GATED_SENSORS,
  REMAP_WSLINK_ITEMS entries
  - utils: voc_level_to_text(),
  battery_5step_to_pct(), connection gating
  - sensors_wslink: HCHO / VOC / T9_BATTERY entity
  descriptions
  - translations (en, cs): hcho, voc (+ states),
  t9_battery
  - tests: tests/conftest.py +
  tests/test_t9_air_quality.py

custom_components/sws12500/const.py

@@ -83,6 +83,10 @@ CH8_BATTERY: Final = "ch8_battery"
 HEAT_INDEX: Final = "heat_index"
 CHILL_INDEX: Final = "chill_index"
 WBGT_TEMP: Final = "wbgt_temp"
+HCHO: Final = "hcho"
+VOC: Final = "voc"
+T9_BATTERY: Final = "t9_battery"  # T9 sensors are HCHO and VOC
+T9_CONN: Final = "t9_conn"
 
 
 # Health specific constants

custom_components/sws12500/utils.py

@@ -24,6 +24,8 @@ from homeassistant.helpers.translation import async_get_translations
 
 from .const import (
     AZIMUT,
+    CONNECTION_GATED_SENSORS,
+    DATABASE_PATH,
     DEV_DBG,
     OUTSIDE_HUMIDITY,
     OUTSIDE_TEMP,
@@ -92,12 +94,7 @@ async def translated_notification(
             persistent_notification.async_create(hass, message, _translations[localize_title], notification_id)
 
 
-async def update_options(
-    hass: HomeAssistant,
-    entry: ConfigEntry,
-    update_key: str,
-    update_value: str | list[str] | bool,
-) -> bool:
+async def update_options(hass: HomeAssistant, entry: ConfigEntry, update_key, update_value) -> bool:
     """Update config.options entry."""
     conf = {**entry.options}
     conf[update_key] = update_value