feat(host_agent): a temperature sensor is judged by how it moves against the CPU (#5783)

A board's spare thermistor inputs report whatever an open input reads, and
the value rule from #5759 only catches the impossible ones. Once an hour,
sensors.refresh judges each sensor against the host's CPU (Package id N,
Tctl/Tdie/TccdN, PECI Agent N) over a week of hourly averages. A sensor is
ruled out if it falls as the CPU warms (r <= -0.5) or holds within 0.5 °C
while the CPU moved 10 °C or more. A judgment needs at least 72 shared hours.

The host temperature leaves judged sensors out at ingest. The host page
lists them under "Not counted", with each reason given once.

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

plugins/host_agent/scheduler.py

@@ -121,6 +121,29 @@ def make_task(app) -> ScheduledTask:
     )
 
 
+def make_sensor_task(app) -> ScheduledTask:
+    """Re-judges which temperature sensors are thermometers (#5783), hourly
+    and at startup, from the hourly averages: verdicts live in memory, so a
+    restart rebuilds them before the first hour is out."""
+    async def _judge():
+        from . import sensors
+        try:
+            async with app.db_sessionmaker() as session:
+                found = await sensors.refresh(session, datetime.now(timezone.utc))
+            for host, labels in found.items():
+                logger.info("host_agent: %s sensors not counted as temperature: %s",
+                            host, ", ".join(sorted(labels)))
+        except Exception:
+            logger.exception("host_agent: judging temperature sensors failed")
+
+    return ScheduledTask(
+        name="host_agent_sensors",
+        coro_factory=_judge,
+        interval_seconds=3600,
+        run_on_startup=True,
+    )
+
+
 def make_maintenance_task(app) -> ScheduledTask:
     """Gives up on maintenance jobs past their deadline (#5767), starts due
     maintenance plans and moves their runs on one host at a time (#5768), and