feat: Refactor rides app with unique constraints, mixins, and enhanced documentation

- Added migration to convert unique_together constraints to UniqueConstraint for RideModel.
- Introduced RideFormMixin for handling entity suggestions in ride forms.
- Created comprehensive code standards documentation outlining formatting, docstring requirements, complexity guidelines, and testing requirements.
- Established error handling guidelines with a structured exception hierarchy and best practices for API and view error handling.
- Documented view pattern guidelines, emphasizing the use of CBVs, FBVs, and ViewSets with examples.
- Implemented a benchmarking script for query performance analysis and optimization.
- Developed security documentation detailing measures, configurations, and a security checklist.
- Compiled a database optimization guide covering indexing strategies, query optimization patterns, and computed fields.

backend/apps/rides/migrations/0026_convert_unique_together_to_constraints.py

@@ -0,0 +1,40 @@
+"""
+Convert RideModel unique_together to UniqueConstraint.
+
+This migration converts the legacy unique_together constraints to the modern
+UniqueConstraint syntax which provides better error messages and more flexibility.
+"""
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('rides', '0025_convert_ride_status_to_fsm'),
+    ]
+
+    operations = [
+        # Remove the old unique_together constraint
+        migrations.AlterUniqueTogether(
+            name='ridemodel',
+            unique_together=set(),
+        ),
+        # Add new UniqueConstraints with better error messages
+        migrations.AddConstraint(
+            model_name='ridemodel',
+            constraint=models.UniqueConstraint(
+                fields=['manufacturer', 'name'],
+                name='ridemodel_manufacturer_name_unique',
+                violation_error_message='A ride model with this name already exists for this manufacturer'
+            ),
+        ),
+        migrations.AddConstraint(
+            model_name='ridemodel',
+            constraint=models.UniqueConstraint(
+                fields=['manufacturer', 'slug'],
+                name='ridemodel_manufacturer_slug_unique',
+                violation_error_message='A ride model with this slug already exists for this manufacturer'
+            ),
+        ),
+    ]