Warn in the navbar when a hard drive runs hot (#470)

* Warn in the navbar when a hard drive runs hot.

The navbar already warns about high CPU temperature; add the equivalent
for drive temperature, since an overheating disk risks data loss and a
user running an off-grid library won't be watching for it.

- controller/lib/smart.py: build_smart_stats() returns the per-drive list
  plus warning thresholds (55C warn / 65C critical) so the frontend stays
  dumb. Reading SMART wakes a spun-down drive, so drives in standby are
  detected with `smartctl -n standby` (which works through the USB-SATA
  bridges where `hdparm -C` only reports "unknown") and NOT read; their
  last-known reading is reused instead.
- controller/lib/status_worker.py: collect SMART on a slow 60s cadence
  (cached on app.state) rather than the 5s status loop, so the poll does
  not keep USB drives awake. The result flows into the same cached payload
  via a new collect_all_status(smart_stats=...) kwarg.
- Frontend: useDriveTemperature() reports the hottest drive; Nav.js shows
  a yellow/red `hdd` icon with a popup, mirroring the CPU warning.

Verified on hardware: smart_stats reports real temps and SMART runs once
a minute, not every 5s.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Address Greptile review on HDD temperature warning.

- _drive_is_asleep also treats SLEEP mode as asleep, not just STANDBY.
  smartctl -n standby exits "Device is in SLEEP mode, exit(2)" for the
  deeper power mode; matching only "STANDBY" meant a SLEEP drive was read
  and woken — the exact failure the check prevents.  (TDD: added a failing
  SLEEP test, then fixed.)
- useDriveTemperature uses ?? instead of || for the temperature fallback
  to express "fall back only on null/undefined".

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

controller/test/test_smart.py

@@ -7,9 +7,13 @@ from unittest import mock
 from controller.lib.smart import (
     is_smart_available,
     get_all_smart_status,
+    build_smart_stats,
     _get_device_smart,
     _get_temperature,
     _get_attribute,
+    _drive_is_asleep,
+    HDD_HIGH_TEMPERATURE,
+    HDD_CRITICAL_TEMPERATURE,
 )
 
 
@@ -203,3 +207,95 @@ class TestGetAttribute:
 
         result = _get_attribute(mock_device, "Power_On_Hours")
         assert result is None
+
+
+class TestDriveIsAsleep:
+    """Tests for _drive_is_asleep function (smartctl -n standby)."""
+
+    def test_returns_true_for_standby(self):
+        completed = mock.Mock(stdout="Device is in STANDBY mode, exit(2)\n")
+        with mock.patch("controller.lib.smart.subprocess.run", return_value=completed):
+            assert _drive_is_asleep("/dev/sda") is True
+
+    def test_returns_true_for_sleep(self):
+        # smartctl -n standby also bails on the deeper SLEEP power mode;
+        # that drive must NOT be woken for a read either.
+        completed = mock.Mock(stdout="Device is in SLEEP mode, exit(2)\n")
+        with mock.patch("controller.lib.smart.subprocess.run", return_value=completed):
+            assert _drive_is_asleep("/dev/sda") is True
+
+    def test_returns_false_for_active(self):
+        # A normal `-i` read on an awake drive never mentions STANDBY.
+        completed = mock.Mock(stdout="Model Family: WDC\nDevice Model: WD100EMAZ\n")
+        with mock.patch("controller.lib.smart.subprocess.run", return_value=completed):
+            assert _drive_is_asleep("/dev/sda") is False
+
+    def test_returns_false_on_error(self):
+        """smartctl missing / errors out → treat as awake (safe fallback)."""
+        with mock.patch("controller.lib.smart.subprocess.run",
+                        side_effect=OSError("boom")):
+            assert _drive_is_asleep("/dev/sda") is False
+
+
+class TestBuildSmartStats:
+    """Tests for build_smart_stats — the navbar/Disk Management payload."""
+
+    def test_returns_thresholds_when_unavailable(self):
+        """Docker / no pySMART → empty drive list but thresholds present."""
+        with mock.patch("controller.lib.smart.is_smart_available", return_value=False):
+            stats = build_smart_stats()
+        assert stats["drives"] == []
+        assert stats["high_temperature"] == HDD_HIGH_TEMPERATURE
+        assert stats["critical_temperature"] == HDD_CRITICAL_TEMPERATURE
+
+    def test_reads_awake_drives(self):
+        fake_device = mock.Mock()
+        fake_device.name = "sda"
+        fake_device.model = "WDC WD100EMAZ"
+        fake_device.serial = "S1"
+        fake_device.capacity = "10.0 TB"
+        fake_device.assessment = "PASS"
+        fake_device.smart_enabled = True
+        fake_device.temperature = 52
+        fake_device.attributes = []
+
+        with mock.patch("controller.lib.smart.is_smart_available", return_value=True), \
+                mock.patch("controller.lib.smart._scan_devices",
+                           return_value=[("/dev/sda", "sat")]), \
+                mock.patch("controller.lib.smart._drive_is_asleep", return_value=False), \
+                mock.patch("controller.lib.smart.Device", return_value=fake_device) as Dev:
+            stats = build_smart_stats()
+
+        Dev.assert_called_once_with("/dev/sda", interface="sat")
+        assert len(stats["drives"]) == 1
+        assert stats["drives"][0]["device"] == "sda"
+        assert stats["drives"][0]["temperature"] == 52
+
+    def test_sleeping_drive_is_not_read_and_reuses_previous(self):
+        """A standby drive must NOT be read (would wake it); reuse old data."""
+        previous = {
+            "drives": [{"device": "sda", "path": "/dev/sda", "temperature": 49}],
+            "high_temperature": HDD_HIGH_TEMPERATURE,
+            "critical_temperature": HDD_CRITICAL_TEMPERATURE,
+        }
+        with mock.patch("controller.lib.smart.is_smart_available", return_value=True), \
+                mock.patch("controller.lib.smart._scan_devices",
+                           return_value=[("/dev/sda", "sat")]), \
+                mock.patch("controller.lib.smart._drive_is_asleep", return_value=True), \
+                mock.patch("controller.lib.smart.Device") as Dev:
+            stats = build_smart_stats(previous=previous)
+
+        Dev.assert_not_called()
+        assert stats["drives"] == [{"device": "sda", "path": "/dev/sda", "temperature": 49}]
+
+    def test_sleeping_drive_without_previous_is_skipped(self):
+        """Standby drive with no prior reading is simply omitted (not hot)."""
+        with mock.patch("controller.lib.smart.is_smart_available", return_value=True), \
+                mock.patch("controller.lib.smart._scan_devices",
+                           return_value=[("/dev/sda", "sat")]), \
+                mock.patch("controller.lib.smart._drive_is_asleep", return_value=True), \
+                mock.patch("controller.lib.smart.Device") as Dev:
+            stats = build_smart_stats(previous=None)
+
+        Dev.assert_not_called()
+        assert stats["drives"] == []