## Feature: Unified History Timeline (HTMX Integrated)

### HTMX Template Pattern
```django
{# history/partials/history_timeline.html #}
<div id="history-timeline" 
     hx-get="{% url 'history:timeline' content_type_id=content_type.id object_id=object.id %}"
     hx-trigger="every 30s, historyUpdate from:body">
  <div class="space-y-4">
    {% for event in events %}
      <div class="component-wrapper bg-white p-4 shadow-sm">
        <div class="component-header flex items-center gap-2 mb-2">
          <span class="text-sm font-medium">{{ event.pgh_label|title }}</span>
          <time class="text-xs text-gray-500">{{ event.pgh_created_at|date:"M j, Y H:i" }}</time>
        </div>
        <div class="component-content text-sm">
          {% if event.pgh_context.metadata.user %}
            <div class="flex items-center gap-1">
              <svg class="w-4 h-4">...</svg>
              <span>{{ event.pgh_context.metadata.user }}</span>
            </div>
          {% endif %}
        </div>
      </div>
    {% endfor %}
  </div>
</div>
```

### View Integration (Class-Based with HTMX)
```python
# history/views.py
class HistoryTimelineView(View):
    def get(self, request, content_type_id, object_id):
        events = ModelHistory.objects.filter(
            pgh_obj_model=content_type_id,
            pgh_obj_id=object_id
        ).order_by('-pgh_created_at')[:25]

        if request.htmx:
            return render(request, "history/partials/history_timeline.html", {
                "events": events
            })
            
        return JsonResponse({
            'history': [serialize_event(e) for e in events]
        })
```

### Event Trigger Pattern
```python
# parks/signals.py
from django.dispatch import Signal
history_updated = Signal()

# In model save/delete handlers:
history_updated.send(sender=Model, instance=instance)