test: kill convert_temp rounding precision mutant (#58)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: deviantintegral <255023+deviantintegral@users.noreply.github.com>

Author: Copilot

tests/test_models.py

@@ -240,6 +240,10 @@ def test_fahrenheit_negative(self):
     def test_fahrenheit_rounding(self):
         assert convert_temp(22.0, TempUnit.FAHRENHEIT) == 71.6
 
+    def test_fahrenheit_rounding_precision(self):
+        """22.3°C -> 72.14°F: round to 1 decimal gives 72.1, not 72.14."""
+        assert convert_temp(22.3, TempUnit.FAHRENHEIT) == 72.1
+
 
 class TestTempSuffix:
     """Tests for temp_suffix()."""