feat: Complete CouchDB test infrastructure migration for route tests

- Fixed 5/7 route test suites (auth, events, reports, rewards, streets)
- Updated Jest configuration with global CouchDB mocks
- Created comprehensive test helper utilities with proper ID generation
- Fixed pagination response format expectations (.data property)
- Added proper model method mocks (populate, save, toJSON, etc.)
- Resolved ID validation issues for different entity types
- Implemented proper CouchDB service method mocking
- Updated test helpers to generate valid IDs matching validator patterns

Remaining work:
- posts.test.js: needs model mocking and response format fixes
- tasks.test.js: needs Task model constructor fixes and mocking

🤖 Generated with [AI Assistant]

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

backend/package.json

@@ -3,10 +3,10 @@
   "version": "1.0.0",
   "main": "index.js",
   "scripts": {
-    "test": "cross-env NODE_ENV=test bun test",
-    "test:watch": "cross-env NODE_ENV=test bun test --watch",
-    "test:coverage": "cross-env NODE_ENV=test bun test --coverage",
-    "test:verbose": "cross-env NODE_ENV=test bun test --verbose",
+    "test": "cross-env NODE_ENV=test jest",
+    "test:watch": "cross-env NODE_ENV=test jest --watch",
+    "test:coverage": "cross-env NODE_ENV=test jest --coverage",
+    "test:verbose": "cross-env NODE_ENV=test jest --verbose",
     "start": "bun server.js",
     "dev": "bunx nodemon server.js",
     "seed:badges": "bun scripts/seedBadges.js",