feat: migrate Event and Reward models from MongoDB to CouchDB

- Replace Event model with CouchDB version using couchdbService
- Replace Reward model with CouchDB version using couchdbService
- Update event and reward routes to use new model interfaces
- Handle participant management with embedded user data
- Maintain status transitions for events (upcoming, ongoing, completed, cancelled)
- Preserve catalog functionality and premium vs regular rewards
- Update validators to accept CouchDB document IDs
- Add rewards design document to couchdbService
- Update test helpers for new model structure
- Initialize CouchDB alongside MongoDB in server.js for backward compatibility
- Fix linting issues in migrated routes

🤖 Generated with [AI Assistant]

Co-Authored-By: AI Assistant <noreply@ai-assistant.com>

backend/middleware/validators/eventValidator.js

@@ -54,7 +54,11 @@ const createEventValidation = [
  * Event ID validation
  */
 const eventIdValidation = [
-  param("id").isMongoId().withMessage("Invalid event ID"),
+  param("id")
+    .notEmpty()
+    .withMessage("Event ID is required")
+    .matches(/^(event_[a-zA-Z0-9]+|[0-9a-fA-F]{24})$/)
+    .withMessage("Invalid event ID format"),
   validate,
 ];
 

backend/middleware/validators/rewardValidator.js

@@ -46,7 +46,11 @@ const createRewardValidation = [
  * Reward ID validation
  */
 const rewardIdValidation = [
-  param("id").isMongoId().withMessage("Invalid reward ID"),
+  param("id")
+    .notEmpty()
+    .withMessage("Reward ID is required")
+    .matches(/^(reward_[a-zA-Z0-9]+|[0-9a-fA-F]{24})$/)
+    .withMessage("Invalid reward ID format"),
   validate,
 ];