Refactor nav_entries_oob into composable shared macro with caller block

Replace the shared fallback template with a Jinja macro that each domain
(blog, events, market) can call with its own domain-specific nav items.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/browser/templates/macros/nav_entries.html

@@ -0,0 +1,58 @@
+{#
+  Composable scrollable nav entries container.
+
+  Usage:
+    {% call nav_entries_oob(has_items=True) %}
+      <a href="..." class="{{styles.nav_button_less_pad}}">...</a>
+      <a href="..." class="{{styles.nav_button_less_pad}}">...</a>
+    {% endcall %}
+
+  Each domain (events, blog, market) provides its own items via the caller block.
+#}
+
+{% macro nav_entries_oob(has_items) %}
+{% if has_items %}
+  <div class="flex flex-col sm:flex-row sm:items-center gap-2 border-r border-stone-200 mr-2 sm:max-w-2xl"
+       id="entries-calendars-nav-wrapper"
+       hx-swap-oob="true">
+    <button
+      class="entries-nav-arrow hidden flex-shrink-0 p-2 hover:bg-stone-200 rounded"
+      aria-label="Scroll left"
+      _="on click
+         set #associated-items-container.scrollLeft to #associated-items-container.scrollLeft - 200">
+      <i class="fa fa-chevron-left"></i>
+    </button>
+
+    <div id="associated-items-container"
+         class="overflow-y-auto sm:overflow-x-auto sm:overflow-y-visible scrollbar-hide max-h-[50vh] sm:max-h-none"
+         style="scroll-behavior: smooth;"
+         _="on load or scroll
+            if window.innerWidth >= 640 and my.scrollWidth > my.clientWidth
+              remove .hidden from .entries-nav-arrow
+              add .flex to .entries-nav-arrow
+            else
+              add .hidden to .entries-nav-arrow
+              remove .flex from .entries-nav-arrow
+            end">
+      <div class="flex flex-col sm:flex-row gap-1">
+        {{ caller() }}
+      </div>
+    </div>
+
+    <style>
+    .scrollbar-hide::-webkit-scrollbar { display: none; }
+    .scrollbar-hide { -ms-overflow-style: none; scrollbar-width: none; }
+    </style>
+
+    <button
+      class="entries-nav-arrow hidden flex-shrink-0 p-2 hover:bg-stone-200 rounded"
+      aria-label="Scroll right"
+      _="on click
+         set #associated-items-container.scrollLeft to #associated-items-container.scrollLeft + 200">
+      <i class="fa fa-chevron-right"></i>
+    </button>
+  </div>
+{% else %}
+  <div id="entries-calendars-nav-wrapper" hx-swap-oob="true"></div>
+{% endif %}
+{% endmacro %}