Show model type in the machines list

The machine's own type is blank for the 134 machines that came from the classic
ASP database on machinetypeid=1, a LocationOnly placeholder the import refuses
to carry across as a real subtype. The catalog model knows what those machines
are, and its type is populated, so the column reads modeltypename under a
heading that says so.

Where both values exist they are identical - all 262 machines in the development
database match exactly - so nothing is lost by showing the one that is reliably
filled in.

This does not fix the underlying gap. A null machinetypeid also excludes a
machine from the map's subtype filter and drops its marker to the default
colour, and no column heading affects that. Only populating machinetypeid does,
which is what the backfill script is for.

plugins/machines/frontend/views/MachinesList.vue

@@ -28,7 +28,7 @@
                 <th>Machine #</th>
                 <th>Name</th>
                 <th>Serial Number</th>
-                <th>Machine Type</th>
+                <th>Model Type</th>
                 <th>Vendor</th>
                 <th>Status</th>
                 <th>Location</th>
@@ -42,7 +42,14 @@
                 </td>
                 <td>{{ item.name || '-' }}</td>
                 <td class="mono">{{ item.serialnumber || '-' }}</td>
-                <td>{{ item.machine?.machinetypename || '-' }}</td>
+                <!--
+                  The catalog model's type, not the machine's own. 134 machines
+                  arrived from the classic ASP database on machinetypeid=1 - a
+                  LocationOnly placeholder the import refuses to carry across as
+                  a real subtype - so Machine Type is blank for them while the
+                  model knows exactly what they are.
+                -->
+                <td>{{ item.machine?.modeltypename || '-' }}</td>
                 <td>{{ item.machine?.vendorname || '-' }}</td>
                 <td>
                   <span class="badge" :style="colorStyle(item.statuscolor)">