perf: add defer to scripts and lazy loading to images

Add defer attribute to 145 <script> tags across 103 template files
(PERF-067) and loading="lazy" to 22 <img> tags across 13 template
files (PERF-058). Both improve page load performance.

Validator totals: 0 errors, 2 warnings, 1360 info (down from 1527).

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

app/modules/core/templates/core/admin/dashboard.html

@@ -137,5 +137,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script src="{{ url_for('core_static', path='admin/js/dashboard.js') }}"></script>
-{% endblock %}
+<script defer src="{{ url_for('core_static', path='admin/js/dashboard.js') }}"></script>
+{% endblock %}

app/modules/core/templates/core/admin/my-menu-config.html

@@ -170,5 +170,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script src="{{ url_for('core_static', path='admin/js/my-menu-config.js') }}"></script>
+<script defer src="{{ url_for('core_static', path='admin/js/my-menu-config.js') }}"></script>
 {% endblock %}

app/modules/core/templates/core/admin/settings.html

@@ -778,5 +778,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script src="{{ url_for('core_static', path='admin/js/settings.js') }}"></script>
+<script defer src="{{ url_for('core_static', path='admin/js/settings.js') }}"></script>
 {% endblock %}

app/modules/core/templates/core/store/dashboard.html

@@ -177,5 +177,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script src="{{ url_for('core_static', path='store/js/dashboard.js') }}"></script>
-{% endblock %}
+<script defer src="{{ url_for('core_static', path='store/js/dashboard.js') }}"></script>
+{% endblock %}

app/modules/core/templates/core/store/settings.html

@@ -1402,5 +1402,5 @@
 {% endblock %}
 
 {% block extra_scripts %}
-<script src="{{ url_for('core_static', path='store/js/settings.js') }}"></script>
+<script defer src="{{ url_for('core_static', path='store/js/settings.js') }}"></script>
 {% endblock %}