fix: use local Chart.js instead of jsdelivr CDN (503 from production)

jsdelivr.net returns 503 from production network (behind FortiGate).
Downloaded Chart.js 4.4.7 UMD bundle locally to eliminate CDN dependency.
Updated all 4 templates that used the CDN link.

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

templates/admin/forum_analytics.html

@@ -465,7 +465,7 @@
     </div>
 </div>
 
-<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script src="{{ url_for('static', filename='js/vendor/chart.min.js') }}"></script>
 {% endblock %}
 
 {% block extra_js %}

templates/admin/social_publisher.html

@@ -674,7 +674,7 @@
 
 <div id="toastContainer" style="position: fixed; top: 80px; right: 20px; z-index: 1100; display: flex; flex-direction: column; gap: 10px;"></div>
 
-<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script src="{{ url_for('static', filename='js/vendor/chart.min.js') }}"></script>
 
 <style>
 .modal-overlay#confirmModal { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0; background: rgba(0,0,0,0.5); z-index: 1050; align-items: center; justify-content: center; }

templates/admin/user_insights.html

@@ -4,7 +4,7 @@
 
 {% block head_extra %}
 {% if tab == 'overview' %}
-<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script src="{{ url_for('static', filename='js/vendor/chart.min.js') }}"></script>
 {% endif %}
 {% endblock %}
 

templates/admin/user_insights_profile.html

@@ -3,7 +3,7 @@
 {% block title %}{{ user.name or user.email }} - Analityka{% endblock %}
 
 {% block head_extra %}
-<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
+<script src="{{ url_for('static', filename='js/vendor/chart.min.js') }}"></script>
 {% endblock %}
 
 {% block extra_css %}