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/ha/test_lifecycle.py

@@ -27,6 +27,11 @@ async def test_setup_reload_unload(hass, entry, inputs):
     assert len(entities) == 5
     ids = {e.unique_id: e.entity_id for e in entities}
     assert coordinator.data["status"] == "learning"
+    status = hass.states.get(ids[f"{entry.entry_id}_status"])
+    assert status.attributes["input_quality"]["rooms"]["sensor.room"]["max_age_seconds_24h"] == 0
+    # Volatile diagnostics stay visible but are not written to the Recorder.
+    assert {"input_quality", "weather_comparison"} <= status.state_info["unrecorded_attributes"]
+    assert "models" not in status.state_info["unrecorded_attributes"]
     proposal_id = registry.async_get_entity_id("binary_sensor", DOMAIN, f"{entry.entry_id}_proposal")
     assert hass.states.get(proposal_id).state == "unavailable"
     assert await hass.config_entries.async_reload(entry.entry_id)