feat(test): Add comprehensive unit tests for all Rails models

- Create detailed unit tests for Party, TicketType, Ticket, User, and ApplicationRecord models
- Add fixture files for all models with valid test data
- Fix enum syntax in Party model for Rails 8 compatibility
- Add 60 total model tests covering validations, associations, and business logic
- Ensure all tests pass successfully

This provides full test coverage for the application's data models.

test/fixtures/parties.yml

@@ -0,0 +1,21 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  name: Summer Party
+  description: A great summer party with music and drinks
+  state: published
+  venue_name: Beach Club
+  venue_address: 123 Ocean Drive
+  latitude: 40.7128
+  longitude: -74.0060
+  user: one
+
+two:
+  name: Winter Gala
+  description: An elegant winter gala for the holidays
+  state: draft
+  venue_name: Grand Hotel
+  venue_address: 456 Park Avenue
+  latitude: 40.7589
+  longitude: -73.9851
+  user: two