adr-028 and int tests

docs/adr/0028-api-response-standardization.md

@@ -2,7 +2,7 @@
 
 **Date**: 2026-01-09
 
-**Status**: Proposed
+**Status**: Implemented
 
 ## Context
 
@@ -99,16 +99,44 @@ interface ApiErrorResponse {
 
 ### What's Implemented
 
-- ❌ Not yet implemented
+- ✅ Created `src/utils/apiResponse.ts` with helper functions (`sendSuccess`, `sendPaginated`, `sendError`, `sendNoContent`, `sendMessage`, `calculatePagination`)
+- ✅ Created `src/types/api.ts` with response type definitions (`ApiSuccessResponse`, `ApiErrorResponse`, `PaginationMeta`, `ErrorCode`)
+- ✅ Updated `src/middleware/errorHandler.ts` to use standard error format
+- ✅ Migrated all route files to use standardized responses:
+  - `health.routes.ts`
+  - `flyer.routes.ts`
+  - `deals.routes.ts`
+  - `budget.routes.ts`
+  - `personalization.routes.ts`
+  - `price.routes.ts`
+  - `reactions.routes.ts`
+  - `stats.routes.ts`
+  - `system.routes.ts`
+  - `gamification.routes.ts`
+  - `recipe.routes.ts`
+  - `auth.routes.ts`
+  - `user.routes.ts`
+  - `admin.routes.ts`
+  - `ai.routes.ts`
 
-### What Needs To Be Done
+### Error Codes
 
-1. Create `src/utils/apiResponse.ts` with helper functions
-2. Create `src/types/api.ts` with response type definitions
-3. Update `errorHandler.ts` to use standard error format
-4. Create migration guide for existing endpoints
-5. Update 2-3 routes as examples
-6. Document pattern in this ADR
+The following error codes are defined in `src/types/api.ts`:
+
+| Code                     | HTTP Status | Description                         |
+| ------------------------ | ----------- | ----------------------------------- |
+| `VALIDATION_ERROR`       | 400         | Request validation failed           |
+| `BAD_REQUEST`            | 400         | Malformed request                   |
+| `UNAUTHORIZED`           | 401         | Authentication required             |
+| `FORBIDDEN`              | 403         | Insufficient permissions            |
+| `NOT_FOUND`              | 404         | Resource not found                  |
+| `CONFLICT`               | 409         | Resource conflict (e.g., duplicate) |
+| `RATE_LIMITED`           | 429         | Too many requests                   |
+| `PAYLOAD_TOO_LARGE`      | 413         | Request body too large              |
+| `INTERNAL_ERROR`         | 500         | Server error                        |
+| `NOT_IMPLEMENTED`        | 501         | Feature not yet implemented         |
+| `SERVICE_UNAVAILABLE`    | 503         | Service temporarily unavailable     |
+| `EXTERNAL_SERVICE_ERROR` | 502         | External service failure            |
 
 ## Example Usage