feat: add source field with 3 options, fix EventListAPI fallback, add is_eventify_event to API response

- Event.source field updated: eventify, community, partner (radio select in form)
- EventListAPI: fallback to all events when pincode returns < 6
- EventListAPI: include is_eventify_event and source in serializer
- Admin API: add source to list serializer
- Django admin: source in list_display, list_filter, list_editable
- Event form template: proper radio button rendering for source field

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

events/forms.py

@@ -36,9 +36,13 @@ class EventForm(forms.ModelForm):
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        # Set source to 'official' only and hide the field
-        self.fields['source'].initial = 'official'
-        self.fields['source'].widget = forms.HiddenInput()
+        # Show source as visible radio buttons with Bootstrap styling
+        self.fields['source'].widget = forms.RadioSelect(
+            choices=self.fields['source'].choices,
+            attrs={'class': 'form-check-input'}
+        )
+        if not self.instance.pk:
+            self.fields['source'].initial = 'eventify'
         
         # Check if all_year_event is True (from instance or initial data)
         all_year_event = False
@@ -60,8 +64,7 @@ class EventForm(forms.ModelForm):
         cleaned_data = super().clean()
         all_year_event = cleaned_data.get('all_year_event', False)
         
-        # Force source to be 'official' only
-        cleaned_data['source'] = 'official'
+        # Source is now user-selectable (eventify/community/partner)
         
         # If all_year_event is True, clear date/time fields
         if all_year_event: