feat: Implement basic general folder support (#2051)

- Related: #1748

tests/ha/get-entity-title.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, it } from 'vitest';
+import { getEntityTitle } from '../../src/ha/get-entity-title';
+import type { HomeAssistant } from '../../src/ha/types';
+import { createHASS, createStateEntity } from '../test-utils';
+
+describe('getEntityTitle', () => {
+  const hass: HomeAssistant = createHASS({
+    'sensor.temperature': createStateEntity({
+      attributes: {
+        friendly_name: 'Temperature Sensor',
+      },
+    }),
+    'light.living_room': createStateEntity({
+      attributes: {
+        friendly_name: 'Living Room Light',
+      },
+    }),
+    'switch.no_friendly': createStateEntity({
+      attributes: {},
+    }),
+  });
+
+  it('returns the friendly_name for a valid entity', () => {
+    expect(getEntityTitle(hass, 'sensor.temperature')).toBe('Temperature Sensor');
+    expect(getEntityTitle(hass, 'light.living_room')).toBe('Living Room Light');
+  });
+
+  it('returns null if the entity does not exist', () => {
+    expect(getEntityTitle(hass, 'sensor.unknown')).toBeNull();
+  });
+
+  it('returns null if hass is undefined', () => {
+    expect(getEntityTitle(undefined, 'sensor.temperature')).toBeNull();
+  });
+
+  it('returns null if entity is undefined', () => {
+    expect(getEntityTitle(hass)).toBeNull();
+  });
+
+  it('returns null if friendly_name attribute is missing', () => {
+    expect(getEntityTitle(hass, 'switch.no_friendly')).toBeNull();
+  });
+
+  it('returns null if both hass and entity are undefined', () => {
+    expect(getEntityTitle()).toBeNull();
+  });
+});