feat(research): add research study management functionality

- Implemented models for ResearchStudy, ResearchStudyArm, and ResearchParticipant.
- Created views for listing, creating, updating, and exporting research studies.
- Added bulk participant generation feature with CSV and JSON support.
- Developed templates for study management, participant entry, and bulk generation.
- Introduced URL routing for research study operations.
- Added utility functions for randomisation and participant assignment.
- Implemented participant intake process with demographic data collection.
- Ensured proper handling of participant CIDs and assignment methods.

research/urls.py

@@ -0,0 +1,23 @@
+from django.urls import path
+from research import views
+
+app_name = "research"
+
+urlpatterns = [
+    # Study management
+    path("", views.study_list, name="study_list"),
+    path("create/", views.study_create, name="study_create"),
+    path("<int:pk>/", views.study_detail, name="study_detail"),
+    path("<int:pk>/update/", views.study_update, name="study_update"),
+    path("<int:pk>/arm/<int:arm_id>/", views.study_arm_update, name="study_arm_update"),
+    
+    # Exports
+    path("<int:pk>/export.csv", views.study_export_csv, name="study_export_csv"),
+    path("<int:pk>/export.json", views.study_export_json, name="study_export_json"),
+    
+    # Bulk generation
+    path("<int:pk>/bulk-generate/", views.study_bulk_generate, name="study_bulk_generate"),
+    
+    # Public participant entry (no login required)
+    path("run/<slug:slug>/<str:pseudo_id>/", views.participant_entry, name="participant_entry"),
+]