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/parks/migrations/0023_add_company_roles_gin_index.py

@@ -0,0 +1,25 @@
+"""
+Add GIN index for Company.roles ArrayField.
+
+This improves query performance for queries like:
+    Company.objects.filter(roles__contains=["MANUFACTURER"])
+    Company.objects.filter(roles__contains=["OPERATOR"])
+
+GIN indexes are specifically designed for array containment queries in PostgreSQL.
+"""
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('parks', '0022_alter_company_roles_alter_companyevent_roles'),
+    ]
+
+    operations = [
+        migrations.RunSQL(
+            sql="CREATE INDEX IF NOT EXISTS parks_company_roles_gin_idx ON parks_company USING gin(roles);",
+            reverse_sql="DROP INDEX IF EXISTS parks_company_roles_gin_idx;",
+        ),
+    ]

backend/apps/parks/migrations/0024_add_timezone_default.py

@@ -0,0 +1,28 @@
+"""
+Add default value 'UTC' to Park.timezone field.
+
+This ensures all new parks have a valid timezone and existing parks
+without a timezone get a sensible default.
+"""
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('parks', '0023_add_company_roles_gin_index'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='park',
+            name='timezone',
+            field=models.CharField(
+                blank=True,
+                default='UTC',
+                help_text="Timezone identifier for park operations (e.g., 'America/New_York')",
+                max_length=50,
+            ),
+        ),
+    ]