TASK22102: slice5 larger file handler contract cleanup

memory-bank/change-log.md

@@ -1437,3 +1437,38 @@ Validation:
 Follow-ups:
 
 - Continue next larger slice on remaining non-proxy file handlers still returning raw error payloads.
+
+---
+
+### CL-039: TASK22102 API contract consistency — Slice 5 (larger file-handler batch)
+
+date: 2026-03-17
+author: Cline
+scope: `pages/api/file/{uploadsinglefile,setupcontainer,createrepcompletemessage_api,editRepJson}.js`
+type: change
+rationale: Continue with a larger efficiency-focused slice by migrating remaining high-signal file handlers that still returned raw/empty error responses.
+impact: Improves response-contract consistency and avoids leaking raw error payloads in selected file handlers while preserving success behavior and endpoint semantics.
+status: completed
+
+Summary:
+
+- Migrated additional file handlers to helper-based responses:
+    - `uploadsinglefile`
+    - `setupcontainer`
+    - `createrepcompletemessage_api`
+    - `editRepJson`
+- Replaced direct `res.status(...).json(...)` error branches (including raw `error` payload and empty responses) with structured:
+    - `respondError(...)`
+    - `respondSuccess(...)`
+- Preserved existing success semantics:
+    - `uploadsinglefile` still returns uploaded result + `invalidFiles`
+    - `setupcontainer` still returns `{ data: "success", output }`
+    - `editRepJson` still returns success message on completion
+
+Validation:
+
+- `npx next lint --file pages/api/file/uploadsinglefile.js --file pages/api/file/setupcontainer.js --file pages/api/file/createrepcompletemessage_api.js --file pages/api/file/editRepJson.js` -> pass (no warnings/errors)
+
+Follow-ups:
+
+- Continue next larger slice on remaining file handlers with empty 400 responses to complete contract-consistency rollout.