[backend/federation] Improve GTS compatibility fixes

Iceshrimp.Backend/Core/Federation/ActivityStreams/Contexts/gts.json

@@ -1,10 +1,22 @@
 {
   "@context": {
     "gts": "https://gotosocial.org/ns#",
-    "interactionPolicy": "gts:interactionPolicy",
-    "canLike": "gts:canLike",
-    "canReply": "gts:canReply",
-    "canAnnounce": "gts:canAnnounce",
+    "interactionPolicy": {
+      "@id": "gts:interactionPolicy",
+      "@type": "@id"
+    },
+    "canLike": {
+      "@id": "gts:canLike",
+      "@type": "@id"
+    },
+    "canReply": {
+      "@id": "gts:canReply",
+      "@type": "@id"
+    },
+    "canAnnounce": {
+      "@id": "gts:canAnnounce",
+      "@type": "@id"
+    },
     "always": {
       "@id": "gts:always",
       "@type": "@id"
@@ -12,6 +24,10 @@
     "approvalRequired": {
       "@id": "gts:approvalRequired",
       "@type": "@id"
+    },
+    "approvedBy": {
+      "@id": "gts:approvedBy",
+      "@type": "@id"
     }
   }
 }