logs para averiaguar el fallo de subida de archivos desde la app

app.js

@@ -55,6 +55,76 @@ app.use((req, res, next) => {
         contentType.toLowerCase().startsWith('multipart/form-data');
 
     if (isMultipartFormData) {
+        const startedAt = process.hrtime.bigint();
+        const baseLogPayload = {
+            request_id: requestId,
+            method: req.method,
+            path: req.originalUrl || req.url,
+            ip: req.ip || null,
+            content_type: contentType,
+            content_length: Number.parseInt(req.get('content-length'), 10) || null,
+            has_authorization_header: Boolean(authorizationHeader),
+            user_agent: String(req.get('user-agent') || '').slice(0, 255) || null
+        };
+        let responseFinished = false;
+
+        appendPostLog({
+            event: 'upload_request_started',
+            ...baseLogPayload
+        });
+
+        res.once('finish', () => {
+            responseFinished = true;
+            const parserStatus = req.uploadDiagnostics?.parser_status || 'not_reached';
+            let failureStage = null;
+
+            if (res.statusCode >= 400) {
+                if (parserStatus === 'rejected') {
+                    failureStage = 'multipart_parser';
+                } else if (parserStatus === 'parsed') {
+                    failureStage = 'controller_or_persistence';
+                } else {
+                    failureStage = 'authentication_rate_limit_or_route';
+                }
+            }
+
+            appendPostLog({
+                event: 'upload_request_finished',
+                ...baseLogPayload,
+                status_code: res.statusCode,
+                duration_ms: Number(
+                    (Number(process.hrtime.bigint() - startedAt) / 1e6).toFixed(2)
+                ),
+                request_complete: req.complete,
+                outcome: res.statusCode < 400 ? 'success' : 'error',
+                failure_stage: failureStage,
+                upload: req.uploadDiagnostics || {
+                    parser_status: 'not_reached'
+                }
+            });
+        });
+
+        res.once('close', () => {
+            if (responseFinished) {
+                return;
+            }
+
+            appendPostLog({
+                event: 'upload_request_interrupted',
+                ...baseLogPayload,
+                status_code: res.statusCode,
+                duration_ms: Number(
+                    (Number(process.hrtime.bigint() - startedAt) / 1e6).toFixed(2)
+                ),
+                request_complete: req.complete,
+                outcome: 'interrupted',
+                failure_stage: 'transport_or_client_disconnect',
+                upload: req.uploadDiagnostics || {
+                    parser_status: 'not_reached'
+                }
+            });
+        });
+
         return next();
     }