fix(theme): hide the map fullscreen button when the map never initialises

The entry-map partial always rendered .feed-map-fullscreen-btn, but the
MapLibre init AND the button's click wiring only run when entries exist —
so on the home pre-departure state (active trip, no published posts) mobile
showed a dead button floating over an empty 40vh map area. Gate the button
on the same entries|length condition as the init script; it reappears with
the first published post, exactly when it becomes functional. Covers any
zero-entry trip page too (shared partial).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0195b3cDdMeize2Mm1FgC2aU

themes/intotheeast/templates/partials/entry-map.html.twig

@@ -23,12 +23,18 @@
 #}
 <div class="home-map-col">
     <div class="home-map" id="{{ map_id }}">
+        {# Same gate as the init script below: without entries the map never
+           initialises and nothing wires the button's click handler, so on
+           mobile (the only viewport where it shows) it would float as a dead
+           control over an empty map area (home pre-departure state). #}
+        {% if entries|length > 0 %}
         <button class="feed-map-fullscreen-btn" id="{{ map_id }}-fullscreen" aria-label="Expand map">
             <svg class="feed-map-fs-open" aria-hidden="true" width="14" height="14" viewBox="0 0 14 14" fill="currentColor">
                 <path d="M0 0v4h1.5V1.5H4V0z M14 0H10v1.5h2.5V4H14z M0 14v-4h1.5v2.5H4V14z M14 14H10v-1.5h2.5V10H14z"/>
             </svg>
             <span class="feed-map-fs-close" aria-hidden="true">✕</span>
         </button>
+        {% endif %}
     </div>
 </div>