add Entra device identity to computers and Azure/Thor import sources

PC records now carry Entra/Azure device identity so imported machines keep a durable link back to their directory object instead of matching on hostname alone. Adds azuredeviceid, azureobjectid, and azuredevicecategory to the Computer model with matching migrations, surfaces them read-only in PCDetail as an Entra Device Info card, and lets PCForm edit the device id directly. The computers plugin registers a machineassetnumber import hook that reconciles PC-to-machine links during bulk import and warns on unresolved or conflicting relationships.

Adds importsources adapters that normalize Azure device-group and Thor PC inventory exports into canonical ShopDB CSVs via hostname alignment, exposes register_import_hook and RowWarning on the shopdb.api contract surface (contract 0.21.0), and refreshes the Import Site Assets page with clearer source instructions. Includes reconcile_locations maintenance script and coverage for the new import paths.

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "shopdb-frontend",
-  "version": "0.7.0",
+  "version": "0.12.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "shopdb-frontend",
-      "version": "0.7.0",
+      "version": "0.12.0",
       "dependencies": {
         "@fontsource-variable/inter": "^5.2.8",
         "@fullcalendar/core": "^6.1.20",