Remove None support from ESPHome supported_frequency_ranges

Always return frequency ranges from device info, matching the
updated RadioFrequencyTransmitterEntity contract.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

homeassistant/components/esphome/radio_frequency.py

@@ -37,12 +37,9 @@ class EsphomeRadioFrequencyEntity(
     """ESPHome radio frequency entity using native API."""
 
     @property
-    def supported_frequency_ranges(self) -> list[tuple[int, int]] | None:
+    def supported_frequency_ranges(self) -> list[tuple[int, int]]:
         """Return supported frequency ranges from device info."""
-        info = self._static_info
-        if info.frequency_min == 0 and info.frequency_max == 0:
-            return None
-        return [(info.frequency_min, info.frequency_max)]
+        return [(self._static_info.frequency_min, self._static_info.frequency_max)]
 
     @callback
     def _on_device_update(self) -> None:

tests/components/esphome/test_radio_frequency.py

@@ -209,27 +209,3 @@ async def test_radio_frequency_supported_frequency_ranges(
         hass, 868_000_000, ModulationType.OOK
     )
     assert len(transmitters) == 0
-
-
-async def test_radio_frequency_no_frequency_ranges(
-    hass: HomeAssistant,
-    mock_client: APIClient,
-    mock_esphome_device: MockESPHomeDeviceType,
-) -> None:
-    """Test entity with no frequency ranges matches any frequency."""
-    await _mock_rf_device(
-        mock_esphome_device,
-        mock_client,
-        frequency_min=0,
-        frequency_max=0,
-    )
-
-    transmitters = radio_frequency.async_get_transmitters(
-        hass, 433_920_000, ModulationType.OOK
-    )
-    assert len(transmitters) == 1
-
-    transmitters = radio_frequency.async_get_transmitters(
-        hass, 868_000_000, ModulationType.OOK
-    )
-    assert len(transmitters) == 1