feat v1.15.0: temperature room fill (blue/green/yellow) with editable comfort bounds

- fill_mode 'temp': below comfort → #4fc3f7, inside → #66d17a, above → #ffd45c;
  bounds default 20-25°C, editable in the space dialog (visible only for this
  mode), swapped bounds tolerated; rooms without a temperature reading unfilled
- areaTemp(): average of the area devices' temperatures
- tests: roomFillColor temp bands + bounds, spaceDisplayOf defaults, areaTemp,
  backend schema (fill_mode temp + temp_min/temp_max); smoke_temp_fill.mjs
- TESTING.md updated in the same commit (policy)

test/devices.test.mjs

@@ -1,6 +1,6 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
-import { buildDevices, lightGroups, primaryEntity, lqiFor, tempFor, areaLights } from '../test-build/devices.js';
+import { buildDevices, lightGroups, primaryEntity, lqiFor, tempFor, areaLights, areaTemp } from '../test-build/devices.js';
 import { compileIconRules } from '../test-build/rules.js';
 
 /** Minimal fake hass around the pieces buildDevices reads. */
@@ -170,3 +170,19 @@ test('areaLights: on / off / none tri-state', () => {
   assert.equal(areaLights(hass, devs, 'kitchen'), 'off');
   assert.equal(areaLights(hass, devs, 'bath'), 'none');
 });
+
+test('areaTemp: averages device temperatures, null when none report', () => {
+  const hass = mkHass({ states: {
+    'sensor.t1': { state: '20.0', attributes: { device_class: 'temperature' } },
+    'sensor.t2': { state: '23.1', attributes: { device_class: 'temperature' } },
+    'sensor.hum': { state: '55', attributes: { device_class: 'humidity' } },
+  }});
+  const devs = [
+    { area: 'living', entities: ['sensor.t1'] },
+    { area: 'living', entities: ['sensor.t2'] },
+    { area: 'bath', entities: ['sensor.hum'] },
+  ];
+  assert.equal(areaTemp(hass, devs, 'living'), 21.6); // (20+23.1)/2=21.55 → 21.6
+  assert.equal(areaTemp(hass, devs, 'bath'), null);
+  assert.equal(areaTemp(hass, devs, 'garage'), null);
+});

test/logic.test.mjs

@@ -239,3 +239,22 @@ test('roomFillColor: lqi gradient, light tri-state, none', () => {
   assert.equal(roomFillColor('light', null, 'off'), '#9aa0a6');
   assert.equal(roomFillColor('light', null, 'none'), null);
 });
+
+test('roomFillColor temp: blue/green/yellow bands, swapped bounds tolerated, no reading → no fill', () => {
+  assert.equal(roomFillColor('temp', null, 'none', 18, 20, 25), '#4fc3f7');  // cold
+  assert.equal(roomFillColor('temp', null, 'none', 20, 20, 25), '#66d17a');  // lower bound inclusive
+  assert.equal(roomFillColor('temp', null, 'none', 25, 20, 25), '#66d17a');  // upper bound inclusive
+  assert.equal(roomFillColor('temp', null, 'none', 26.5, 20, 25), '#ffd45c'); // hot
+  assert.equal(roomFillColor('temp', null, 'none', 18, 25, 20), '#4fc3f7');  // swapped bounds
+  assert.equal(roomFillColor('temp', null, 'none', null, 20, 25), null);
+  assert.equal(roomFillColor('temp', null, 'none', undefined, 20, 25), null);
+});
+
+test('spaceDisplayOf: temp bounds default to 20..25 and accept overrides', () => {
+  const d = spaceDisplayOf({ plan_url: '/x.svg' });
+  assert.equal(d.tempMin, 20);
+  assert.equal(d.tempMax, 25);
+  const o = spaceDisplayOf({ settings: { temp_min: 18.5, temp_max: 23 } });
+  assert.equal(o.tempMin, 18.5);
+  assert.equal(o.tempMax, 23);
+});