Fix software-compliance report + relationshiptypes zero-dates

- Add applications.isrequired (model + migration 7c02 + create/update + form
  checkbox). The software-compliance report compared required apps against
  installs but no such flag existed, so it 500'd; now it works.
- Repair relationshiptypes rows with 0000-00-00 createddate/modifieddate
  (partof/connectedto) to real timestamps.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/applications/ApplicationForm.vue

@@ -65,6 +65,10 @@
               <input type="checkbox" v-model="form.isprinter" />
               Printer App
             </label>
+            <label>
+              <input type="checkbox" v-model="form.isrequired" />
+              Required on all PCs
+            </label>
             <label>
               <input type="checkbox" v-model="form.ishidden" />
               Hidden
@@ -168,6 +172,7 @@ const form = ref({
   isinstallable: false,
   islicenced: false,
   isprinter: false,
+  isrequired: false,
   ishidden: false,
   applicationlink: '',
   documentationpath: '',
@@ -196,6 +201,7 @@ onMounted(async () => {
         isinstallable: app.isinstallable || false,
         islicenced: app.islicenced || false,
         isprinter: app.isprinter || false,
+        isrequired: app.isrequired || false,
         ishidden: app.ishidden || false,
         applicationlink: app.applicationlink || '',
         documentationpath: app.documentationpath || '',
@@ -224,6 +230,7 @@ async function saveApplication() {
       isinstallable: form.value.isinstallable,
       islicenced: form.value.islicenced,
       isprinter: form.value.isprinter,
+      isrequired: form.value.isrequired,
       ishidden: form.value.ishidden,
       applicationlink: form.value.applicationlink || null,
       documentationpath: form.value.documentationpath || null,