Notification updates

CLAUDE.md

@@ -19,6 +19,32 @@ Maintain professional documentation standards without emoji usage.
 - **Delete** old code when replacing it
 - **Meaningful names**: `userID` not `id`
 
+## Naming Conventions
+
+### Case Standards
+| Layer | Convention | Example |
+|-------|------------|---------|
+| Database columns | snake_case | `user_id`, `created_at`, `is_active` |
+| Backend TypeScript types | camelCase | `userId`, `createdAt`, `isActive` |
+| API responses | camelCase | `{ "userId": "...", "createdAt": "..." }` |
+| Frontend TypeScript types | camelCase | `userId`, `createdAt`, `isActive` |
+
+### Repository Pattern for Case Conversion
+All repositories MUST implement private `mapRow()` or similar mapper functions to convert database snake_case to TypeScript camelCase:
+
+```typescript
+private mapRow(row: any): MyType {
+  return {
+    id: row.id,
+    userId: row.user_id,      // snake_case -> camelCase
+    createdAt: row.created_at,
+    isActive: row.is_active,
+  };
+}
+```
+
+All methods returning data to the API must use these mappers - never return raw database rows.
+
 ## Docker-First Implementation Strategy
 
 ### 1. Package.json Updates Only