display_name → at_handle for every user-rendering point around the recent-activity surfaces: scroll.html actor <strong>, Most Recent Scroll applet actor <strong>, My Games row body actor prefix, My Scrolls row body actor prefix, My Buds page bud-name span, navbar identity, _bud_panel.html data-sharer-name (consumed by the dynamic post-line-author append on share success) — at_handle was always the right filter for these slots: it produces @<username> when the user has set one, falling back to the truncated email (which already carries an @) so we don't double-prefix; the _my_buds_applet_item.html row was already on at_handle from the 3-col sprint, so this commit just brings the rest of the surfaces in line; _navbar.html swap also drops the literal @ that prefixed {{ user|display_name }} — that literal predated at_handle + worked for users w. usernames (gave @disco) but produced @<email>@<domain> for users w. no username yet; navbar wait_to_be_logged_in(email) FT helper keeps working since the email still appears as a substring whether rendered as @disco@test.io (old, no username) or disco@test.io (new); _bud_add_panel.html's client-side _appendBudEntry JS gains an inline at_handle mirror — display.indexOf('@') >= 0 ? display : '@' + display — since the server's add_bud response packs username or email under the username key (semantic mismatch w. the key name but stable) so the JS has to detect the email case itself; test_bill_my_buds.py two .bud-name text assertions ("alice" → "@alice") updated for the new prefix; 931 ITs + targeted FT regression on test_bill_my_buds + test_core_navbar + test_core_login green

src/templates/apps/billboard/_partials/_applet-most-recent-scroll.html

@@ -11,7 +11,7 @@
             {% for event in recent_events %}
                 <div class="drama-event {% if event.actor == viewer %}mine{% elif event.actor %}theirs{% else %}system{% endif %}">
                     <span class="drama-event-body{% if event.struck %} struck{% endif %}">
-                        {% if event.actor %}<strong>{{ event.actor|display_name }}</strong>{% endif %}
+                        {% if event.actor %}<strong>{{ event.actor|at_handle }}</strong>{% endif %}
                         {{ event.to_prose|safe }}
                     </span>
                     <time class="drama-event-time" datetime="{{ event.timestamp|date:'c' }}">

src/templates/apps/billboard/_partials/_bud_add_panel.html

@@ -46,7 +46,12 @@
         li.dataset.budId = bud.id;
         var name = document.createElement('span');
         name.className = 'bud-name';
-        name.textContent = bud.username;
+        // Mirror the `at_handle` template filter: prefix `@` on plain
+        // usernames; leave the value untouched if it already contains
+        // `@` (the server falls back to email when username is unset,
+        // and emails don't take the prefix).
+        var display = bud.username || '';
+        name.textContent = display.indexOf('@') >= 0 ? display : '@' + display;
         li.appendChild(name);
         var buffer = list.querySelector('.bud-entry-buffer');
         if (buffer) list.insertBefore(li, buffer);

src/templates/apps/billboard/_partials/_bud_panel.html

@@ -16,7 +16,7 @@
 </button>
 
 <div id="id_bud_panel"
-     data-sharer-name="{% if request.user.is_authenticated %}{{ request.user|display_name }}{% endif %}">
+     data-sharer-name="{% if request.user.is_authenticated %}{{ request.user|at_handle }}{% endif %}">
     <input id="id_recipient"
            name="recipient"
            type="text"

src/templates/apps/billboard/_partials/_my_buds_item.html

@@ -1,4 +1,4 @@
 {% load lyric_extras %}
 <li class="applet-list-entry bud-entry" data-bud-id="{{ item.id }}">
-    <span class="bud-name">{{ item|display_name }}</span>
+    <span class="bud-name">{{ item|at_handle }}</span>
 </li>

src/templates/apps/billboard/_partials/_my_scrolls_item.html

@@ -8,7 +8,7 @@
 <li class="applet-list-entry row-3col">
     <a href="{% url 'billboard:scroll' item.id %}" class="row-title">{{ item.name|truncate_title }}</a>
     {% if item.latest_event %}
-        <span class="row-body">{% if item.latest_event.actor %}{{ item.latest_event.actor|display_name }} {% endif %}{{ item.latest_event.to_prose|striptags }}</span>
+        <span class="row-body">{% if item.latest_event.actor %}{{ item.latest_event.actor|at_handle }} {% endif %}{{ item.latest_event.to_prose|striptags }}</span>
         <time class="row-ts" datetime="{{ item.latest_event.timestamp|date:'c' }}">{{ item.latest_event.timestamp|relative_ts }}</time>
     {% endif %}
 </li>