Semantic Search Triggers (#18969)

* semantic trigger test

* database and model

* config

* embeddings maintainer and trigger post-processor

* api to create, edit, delete triggers

* frontend and i18n keys

* use thumbnail and description for trigger types

* image picker tweaks

* initial sync

* thumbnail file management

* clean up logs and use saved thumbnail on frontend

* publish mqtt messages

* webpush changes to enable trigger notifications

* add enabled switch

* add triggers from explore

* renaming and deletion fixes

* fix typing

* UI updates and add last triggering event time and link

* log exception instead of return in endpoint

* highlight entry in UI when triggered

* save and delete thumbnails directly

* remove alert action for now and add descriptions

* tweaks

* clean up

* fix types

* docs

* docs tweaks

* docs

* reuse enum

web/public/locales/en/components/dialog.json

@@ -109,5 +109,12 @@
       "markAsReviewed": "Mark as reviewed",
       "deleteNow": "Delete Now"
     }
+  },
+  "imagePicker": {
+    "selectImage": "Select a tracked object's thumbnail",
+    "search": {
+      "placeholder": "Search by label or sub label..."
+    },
+    "noImages": "No thumbnails found for this camera"
   }
 }