fix(demo): scale MonitorTag.MinDuration to datenum time base

MonitorTag.applyDebounce_ measures run duration in parent-X native
units. plantConfig expresses MinDuration in seconds (1 / 2 / 3), which
was correct while the data generator emitted posix seconds as the
time base. After the datenum switch, parent-X is in days — so a
config value of '1 second' was being treated as '1 day' of debounce,
and every 3-second breach (3.5e-5 days) was quietly zeroed out by the
debounce filter before it could fire the monitor.

Divide each MinDuration by 86400 when constructing the MonitorTags in
registerPlantTags, so the demo's monitors keep human-readable seconds
in plantConfig while the instantiated tags use the correct datenum
units on the wire. Criticality and AlarmOff predicates are unaffected
(the AlarmOff condition is evaluated on Y, not on X).

Regression suite: 80/80 green.

Author: HanSur94

demo/industrial_plant/private/registerPlantTags.m

@@ -94,10 +94,18 @@
 
     mDefs = cfg.MonitorDefs;  % expects 4 entries in fixed order, see plantConfig
 
+    % MonitorTag.MinDuration is expressed in parent-X native units. The
+    % demo's parent SensorTags carry time as MATLAB datenum (days since
+    % 0000-01-00), so a config value of "1 second" must be rescaled to
+    % 1/86400 days. Without this, a 3-second breach reads as 3.5e-5 days
+    % and always falls below the 1-day debounce window → monitor never
+    % fires and StatusWidget / IconCardWidget stay green.
+    secondsPerDay = 86400;
+
     mFeedlinePressureHigh = MonitorTag(mDefs(1).Key, ...
         TagRegistry.get(mDefs(1).ParentKey), mDefs(1).ConditionFn, ...
         'AlarmOffConditionFn', mDefs(1).AlarmOffFn, ...
-        'MinDuration',         mDefs(1).MinDuration, ...
+        'MinDuration',         mDefs(1).MinDuration / secondsPerDay, ...
         'Criticality',         mDefs(1).Criticality, ...
         'EventStore',          store, ...
         'Name',                prettyName_(mDefs(1).Key));
@@ -106,7 +114,7 @@
     mReactorPressureCritical = MonitorTag(mDefs(2).Key, ...
         TagRegistry.get(mDefs(2).ParentKey), mDefs(2).ConditionFn, ...
         'AlarmOffConditionFn', mDefs(2).AlarmOffFn, ...
-        'MinDuration',         mDefs(2).MinDuration, ...
+        'MinDuration',         mDefs(2).MinDuration / secondsPerDay, ...
         'Criticality',         mDefs(2).Criticality, ...
         'EventStore',          store, ...
         'Name',                prettyName_(mDefs(2).Key));
@@ -115,7 +123,7 @@
     mReactorTemperatureHigh = MonitorTag(mDefs(3).Key, ...
         TagRegistry.get(mDefs(3).ParentKey), mDefs(3).ConditionFn, ...
         'AlarmOffConditionFn', mDefs(3).AlarmOffFn, ...
-        'MinDuration',         mDefs(3).MinDuration, ...
+        'MinDuration',         mDefs(3).MinDuration / secondsPerDay, ...
         'Criticality',         mDefs(3).Criticality, ...
         'EventStore',          store, ...
         'Name',                prettyName_(mDefs(3).Key));
@@ -124,7 +132,7 @@
     mCoolingFlowLow = MonitorTag(mDefs(4).Key, ...
         TagRegistry.get(mDefs(4).ParentKey), mDefs(4).ConditionFn, ...
         'AlarmOffConditionFn', mDefs(4).AlarmOffFn, ...
-        'MinDuration',         mDefs(4).MinDuration, ...
+        'MinDuration',         mDefs(4).MinDuration / secondsPerDay, ...
         'Criticality',         mDefs(4).Criticality, ...
         'EventStore',          store, ...
         'Name',                prettyName_(mDefs(4).Key));