Refactor model imports and update admin classes to use pghistory for historical tracking; replace HistoricalModel with TrackedModel in relevant models

companies/admin.py

@@ -1,16 +1,15 @@
 from django.contrib import admin
-from simple_history.admin import SimpleHistoryAdmin
 from .models import Company, Manufacturer
 
 @admin.register(Company)
-class CompanyAdmin(SimpleHistoryAdmin):
+class CompanyAdmin(admin.ModelAdmin):
     list_display = ('id', 'name', 'headquarters', 'website', 'created_at')
     search_fields = ('name', 'headquarters', 'description')
     prepopulated_fields = {'slug': ('name',)}
     readonly_fields = ('created_at', 'updated_at')
 
 @admin.register(Manufacturer)
-class ManufacturerAdmin(SimpleHistoryAdmin):
+class ManufacturerAdmin(admin.ModelAdmin):
     list_display = ('id', 'name', 'headquarters', 'website', 'created_at')
     search_fields = ('name', 'headquarters', 'description')
     prepopulated_fields = {'slug': ('name',)}