Add "sign in to participate" message to public toot page (#8200)

app/javascript/styles/mastodon/stream_entries.scss

@@ -37,7 +37,8 @@
 
     &:last-child {
       .detailed-status,
-      .status {
+      .status,
+      .load-more {
         border-bottom: 0;
         border-radius: 0 0 4px 4px;
       }
@@ -45,13 +46,15 @@
 
     &:first-child {
       .detailed-status,
-      .status {
+      .status,
+      .load-more {
         border-radius: 4px 4px 0 0;
       }
 
       &:last-child {
         .detailed-status,
-        .status {
+        .status,
+        .load-more {
           border-radius: 4px;
         }
       }
@@ -59,7 +62,8 @@
 
     @media screen and (max-width: 740px) {
       .detailed-status,
-      .status {
+      .status,
+      .load-more {
         border-radius: 0 !important;
       }
     }

app/views/stream_entries/_status.html.haml

@@ -53,3 +53,9 @@
   - if @next_descendant_thread
     .entry{ class: entry_classes }
       = link_to_more short_account_status_url(status.account.username, status, since_descendant_thread_id: @max_descendant_thread_id - 1)
+
+- if include_threads && !embedded_view? && !user_signed_in?
+  .entry{ class: entry_classes }
+    = link_to new_user_session_path, class: 'load-more load-gap' do
+      = fa_icon 'comments'
+      = t('statuses.sign_in_to_participate')

config/locales/en.yml

@@ -746,6 +746,7 @@ en:
       private: Non-public toot cannot be pinned
       reblog: A boost cannot be pinned
     show_more: Show more
+    sign_in_to_participate: Sign in to participate in the conversation
     title: '%{name}: "%{quote}"'
     visibilities:
       private: Followers-only