fix(web): correct UTC timestamp parsing in monitoring panel

Backend serializes monitoring timestamps as naive ISO strings without
timezone designator. JavaScript's new Date() treats such strings as
local time, causing displayed times to be off by the user's UTC offset.
Add parseUTCTimestamp() utility that appends 'Z' to ensure correct UTC
interpretation.

web/src/app/home/pipelines/components/monitoring-tab/PipelineMonitoringTab.tsx

@@ -10,6 +10,7 @@ import { MessageContentRenderer } from '@/app/home/monitoring/components/Message
 import { LoadingSpinner } from '@/components/ui/loading-spinner';
 import { httpClient } from '@/app/infra/http/HttpClient';
 import { MessageDetails } from '@/app/home/monitoring/types/monitoring';
+import { parseUTCTimestamp } from '@/app/home/monitoring/utils/dateUtils';
 
 interface PipelineMonitoringTabProps {
   pipelineId: string;
@@ -120,7 +121,7 @@ export default function PipelineMonitoringTab({
                 message: result.message
                   ? {
                       id: result.message.id,
-                      timestamp: new Date(result.message.timestamp),
+                      timestamp: parseUTCTimestamp(result.message.timestamp),
                       botId: result.message.bot_id,
                       botName: result.message.bot_name,
                       pipelineId: result.message.pipeline_id,
@@ -137,7 +138,7 @@ export default function PipelineMonitoringTab({
                   : undefined,
                 llmCalls: result.llm_calls.map((call: RawLLMCallData) => ({
                   id: call.id,
-                  timestamp: new Date(call.timestamp),
+                  timestamp: parseUTCTimestamp(call.timestamp),
                   modelName: call.model_name,
                   status: call.status,
                   duration: call.duration,
@@ -150,7 +151,7 @@ export default function PipelineMonitoringTab({
                 })),
                 errors: result.errors.map((error: RawErrorData) => ({
                   id: error.id,
-                  timestamp: new Date(error.timestamp),
+                  timestamp: parseUTCTimestamp(error.timestamp),
                   errorType: error.error_type,
                   errorMessage: error.error_message,
                   stackTrace: error.stack_trace,