Fix invalid device_class + unit_of_measurement combinations for HA 2026.5 (#32)

HA 2026.5 enforces strict validation of device_class/unit_of_measurement
pairs in MQTT discovery payloads. Four categories were broken:

- power_factor: unit was sent as "power_factor" (the FIMP field name); HA
  requires the field to be omitted or empty for this device class. Fixed by
  normalising the display unit separately from the FIMP data-path key.

- illuminance: unit "Lux" is rejected; normalise to "lx". When a sensor
  reports luminance as "%" (some Z-Wave devices), the illuminance device
  class is dropped so the entity becomes a generic sensor rather than
  triggering a validation error.

- reactive_power (regular/export meter): unit "VAr" is rejected; HA requires
  lowercase "var".

- reactive_power (extended meter values, e.g. p_import_react): the unit
  determination logic fell through to the generic power branch and sent "W";
  reactive power extended values now emit "var", apparent power values emit
  "VA", and reactive energy values emit "kvarh".

Fixes #31

Co-authored-by: Claude <noreply@anthropic.com>

futurehome/src/services/_meter.ts

@@ -370,16 +370,25 @@ export function _meter__components(
           break;
       }
 
+      // Map FIMP unit names to HA-compatible unit_of_measurement values
+      const haUnit =
+        unit === 'power_factor' ? '' :
+        unit === 'VAr' ? 'var' :
+        unit === 'kVArh' ? 'kvarh' : unit;
+
       const component: SensorComponent = {
         unique_id: componentId,
         platform: 'sensor',
         entity_category: 'diagnostic',
         name: friendlyName,
-        unit_of_measurement: unit,
         state_class: stateClass,
         value_template: `{{ value_json['${svc.addr}'].meter.${unit}.val | default(0) }}`,
       };
 
+      if (haUnit) {
+        component.unit_of_measurement = haUnit;
+      }
+
       if (deviceClass) {
         component.device_class = deviceClass;
       }
@@ -460,16 +469,24 @@ export function _meter__components(
           break;
       }
 
+      // Map FIMP unit names to HA-compatible unit_of_measurement values
+      const haUnit =
+        unit === 'VAr' ? 'var' :
+        unit === 'kVArh' ? 'kvarh' : unit;
+
       const component: SensorComponent = {
         unique_id: componentId,
         platform: 'sensor',
         entity_category: 'diagnostic',
         name: friendlyName,
-        unit_of_measurement: unit,
         state_class: stateClass,
         value_template: `{{ value_json['${svc.addr}'].meter_export.${unit}.val | default(0) }}`,
       };
 
+      if (haUnit) {
+        component.unit_of_measurement = haUnit;
+      }
+
       if (deviceClass) {
         component.device_class = deviceClass;
       }
@@ -510,14 +527,25 @@ export function _meter__components(
 
       // Determine unit based on value name
       let unit = '';
-      if (
+      const isPhasePower =
         valueName.startsWith('p_') ||
         valueName.startsWith('p1') ||
         valueName.startsWith('p2') ||
-        valueName.startsWith('p3') ||
+        valueName.startsWith('p3');
-        valueName === 'dc_p'
+      if (isPhasePower && valueName.includes('_react')) {
-      ) {
+        unit = 'var';
+      } else if (isPhasePower && valueName.includes('_apparent')) {
+        unit = 'VA';
+      } else if (isPhasePower || valueName === 'dc_p') {
         unit = 'W';
+      } else if (
+        (valueName.startsWith('e_') ||
+          valueName.startsWith('e1') ||
+          valueName.startsWith('e2') ||
+          valueName.startsWith('e3')) &&
+        valueName.includes('_react')
+      ) {
+        unit = 'kvarh';
       } else if (
         valueName.startsWith('e_') ||
         valueName.startsWith('e1') ||
@@ -565,9 +593,9 @@ export function _meter__components(
       }
 
       // Set suggested display precision
-      if (unit === 'kWh') {
+      if (unit === 'kWh' || unit === 'kvarh') {
         component.suggested_display_precision = 3;
-      } else if (unit === 'W' || unit === 'V' || unit === 'A') {
+      } else if (unit === 'W' || unit === 'V' || unit === 'A' || unit === 'var' || unit === 'VA') {
         component.suggested_display_precision = 1;
       } else if (unit === 'Hz') {
         component.suggested_display_precision = 2;

futurehome/src/services/_sensor_numeric.ts

@@ -72,12 +72,15 @@ export function _sensor_numeric__components(
 
   if (!data) return undefined;
 
-  const device_class = data[0];
+  let device_class = data[0];
   const name = data[1];
   let unit = svc.props?.sup_units?.[0] ?? data[2];
   if (unit === 'C') unit = '°C';
   if (unit === 'F') unit = '°F';
   if (unit === 'kph') unit = 'km/h';
+  if (unit === 'Lux') unit = 'lx';
+  // HA rejects illuminance + %; drop device_class for percentage-reporting sensors
+  if (device_class === 'illuminance' && unit === '%') device_class = undefined;
   const state_class = data[3];
 
   return {