TASK22102: slice3 migrate file proxy handlers

memory-bank/change-log.md

@@ -1371,3 +1371,35 @@ Validation:
 Follow-ups:
 
 - Next slice can target selected file handlers for equivalent response contract cleanup.
+
+---
+
+### CL-037: TASK22102 API contract consistency — Slice 3 (file proxy handlers)
+
+date: 2026-03-17
+author: Cline
+scope: `pages/api/file/{getbloblistproxy,getrepsblobproxy,getawaitingsubmissionfromblobproxy,createappealcompletemessageproxy_api}.js`
+type: change
+rationale: Extend contract consistency into selected proxy file handlers by replacing raw error passthrough and empty 400s with standardized structured responses.
+impact: Improves API error contract clarity for selected file proxy routes while preserving success payload pass-through behavior.
+status: completed
+
+Summary:
+
+- Migrated selected file proxy handlers to shared response helper usage:
+    - `getbloblistproxy`
+    - `getrepsblobproxy`
+    - `getawaitingsubmissionfromblobproxy`
+    - `createappealcompletemessageproxy_api`
+- Replaced direct `res.status(...).json(...)` handling with:
+    - `respondSuccess(...)`
+    - `respondError(...)`
+- Added explicit structured 400 responses for missing required query values and proxy fetch failures.
+
+Validation:
+
+- `npx next lint --file pages/api/file/getbloblistproxy.js --file pages/api/file/getrepsblobproxy.js --file pages/api/file/getawaitingsubmissionfromblobproxy.js --file pages/api/file/createappealcompletemessageproxy_api.js` -> pass (no warnings/errors)
+
+Follow-ups:
+
+- Next slice should target non-proxy file handlers that still return raw `error` payloads.