Revert "Do not prefer sharedinbox"

This reverts commit 3389730242.

src/apub.rs

@@ -81,9 +81,17 @@ pub struct AcceptedActors {
 
     pub inbox: XsdAnyUri,
 
+    pub endpoints: Endpoints,
+
     pub public_key: PublicKey,
 }
 
+#[derive(Clone, Debug, serde::Deserialize, serde::Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Endpoints {
+    shared_inbox: Option<XsdAnyUri>,
+}
+
 impl PublicKey {
     pub fn to_ext(self) -> PublicKeyExtension {
         self.into()
@@ -174,6 +182,6 @@ impl ValidObjects {
 
 impl AcceptedActors {
     pub fn inbox(&self) -> &XsdAnyUri {
-        &self.inbox
+        self.endpoints.shared_inbox.as_ref().unwrap_or(&self.inbox)
     }
 }