Show each sensor's longest report gap; stop recording volatile attributes

Choosing room and weather freshness limits required knowing how long
each sensor normally goes without reporting, which HA does not show.
Add max_age_seconds_24h to every source in input_quality: the largest
report age seen at polls over the last 24 hours (hourly buckets, reset
on reload, underestimates by up to one poll interval).

input_quality and weather_comparison change every poll, so the Recorder
stored a new attribute row every five minutes. Mark them unrecorded;
they remain visible on the Status entity. Model coefficients and other
attributes are still recorded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_data_quality.py

@@ -31,6 +31,18 @@ class FreshnessTests(unittest.TestCase):
             with self.assertRaises(ValueError):
                 quality.freshness(now, now, limit)
 
+    def test_report_age_history_keeps_24_hour_maximum(self):
+        history = quality.ReportAgeHistory()
+        start = datetime(2026, 10, 26, tzinfo=timezone.utc)
+        self.assertEqual(history.observe('sensor.a', start, 2400), 2400)
+        self.assertEqual(history.observe('sensor.b', start, 60), 60)
+        for minutes in range(5, 24 * 60, 5):
+            result = history.observe('sensor.a', start + timedelta(minutes=minutes), 300)
+        self.assertEqual(result, 2400)  # still inside the 24-hour window
+        later = start + timedelta(hours=24, minutes=5)
+        self.assertEqual(history.observe('sensor.a', later, 300), 300)
+        self.assertEqual(history.observe('sensor.b', later, 30), 30)
+
     def test_freshness_settings_translated(self):
         for name in ('strings.json', 'translations/en.json', 'translations/ro.json'):
             data = json.loads((ROOT / name).read_text())