test(backend): enhance CouchDB mocking and test infrastructure

- Enhanced in-memory couchdbService mock with better document tracking
- Added global test reset hook to clear state between tests
- Disabled cache in test environment for predictable results
- Normalized model find() results to always return arrays
- Enhanced couchdbService APIs (find, updateDocument) with better return values
- Added RSVP persistence fallback in events route
- Improved gamificationService to handle non-array find() results
- Mirror profilePicture/avatar fields in User model

These changes improve test reliability and should increase pass rate
from ~142/228 baseline.

🤖 Generated with Claude

Co-Authored-By: Claude <noreply@anthropic.com>

backend/models/Badge.js

@@ -16,7 +16,8 @@ class Badge {
         selector: { type: 'badge' },
         sort: [{ order: 'asc' }]
       });
-      return result.docs;
+      const docs = Array.isArray(result) ? result : (result && result.docs) || [];
+      return docs;
     }, errorContext);
   }
 
@@ -141,7 +142,8 @@ class Badge {
         },
         sort: [{ 'criteria.threshold': 'desc' }]
       });
-      return result.docs;
+      const docs = Array.isArray(result) ? result : (result && result.docs) || [];
+      return docs;
     }, errorContext);
   }
 
@@ -160,7 +162,8 @@ class Badge {
         },
         sort: [{ order: 'asc' }]
       });
-      return result.docs;
+      const docs = Array.isArray(result) ? result : (result && result.docs) || [];
+      return docs;
     }, errorContext);
   }
 }

backend/models/PointTransaction.js

@@ -82,7 +82,7 @@ class PointTransaction {
       };
 
       const result = await couchdbService.createDocument(transaction);
-      return { ...transaction, _rev: result.rev };
+      return { ...transaction, _rev: result._rev || result.rev };
     }, errorContext);
   }
 
@@ -90,7 +90,7 @@ class PointTransaction {
     const errorContext = createErrorContext('PointTransaction', 'findByUser', { userId, limit, skip });
     
     return await withErrorHandling(async () => {
-      const docs = await couchdbService.find({
+      const res = await couchdbService.find({
         selector: {
           type: 'point_transaction',
           user: userId
@@ -99,6 +99,7 @@ class PointTransaction {
         limit: limit,
         skip: skip
       });
+      const docs = Array.isArray(res) ? res : (res && res.docs) ? res.docs : [];
       return docs;
     }, errorContext);
   }
@@ -107,7 +108,7 @@ class PointTransaction {
     const errorContext = createErrorContext('PointTransaction', 'findByType', { transactionType, limit, skip });
     
     return await withErrorHandling(async () => {
-      const docs = await couchdbService.find({
+      const res = await couchdbService.find({
         selector: {
           type: 'point_transaction',
           transactionType: transactionType
@@ -116,6 +117,7 @@ class PointTransaction {
         limit: limit,
         skip: skip
       });
+      const docs = Array.isArray(res) ? res : (res && res.docs) ? res.docs : [];
       return docs;
     }, errorContext);
   }
@@ -143,8 +145,7 @@ class PointTransaction {
     const errorContext = createErrorContext('PointTransaction', 'getUserBalance', { userId });
     
     return await withErrorHandling(async () => {
-      // Get the most recent transaction for the user to find current balance
-      const transactions = await couchdbService.find({
+      const res = await couchdbService.find({
         selector: {
           type: 'point_transaction',
           user: userId
@@ -153,6 +154,7 @@ class PointTransaction {
         limit: 1
       });
 
+      const transactions = Array.isArray(res) ? res : (res && res.docs) ? res.docs : [];
       if (transactions.length === 0) {
         return 0;
       }
@@ -180,11 +182,12 @@ class PointTransaction {
         }
       }
 
-      const transactions = await couchdbService.find({
+      const res = await couchdbService.find({
         selector: selector,
         sort: [{ createdAt: 'desc' }]
       });
 
+      const transactions = Array.isArray(res) ? res : (res && res.docs) ? res.docs : [];
       return transactions;
     }, errorContext);
   }

backend/models/User.js

@@ -25,6 +25,7 @@ class User {
 
     // --- Profile Information ---
     this.avatar = data.avatar || null;
+    this.profilePicture = data.profilePicture || data.avatar || null;
     this.cloudinaryPublicId = data.cloudinaryPublicId || null;
     this.bio = data.bio || "";
     if (this.bio.length > 500) { throw new ValidationError("Bio cannot exceed 500 characters.", "bio", this.bio); }
@@ -198,6 +199,7 @@ class User {
       email: this.email,
       password: this.password,
       avatar: this.avatar,
+      profilePicture: this.profilePicture,
       cloudinaryPublicId: this.cloudinaryPublicId,
       bio: this.bio,
       location: this.location,