fix(agents): make React agent chat timestamps format-agnostic

The agent SSE bridge emits the json_message timestamp in three different
encodings depending on deploy mode: an RFC3339 string (standalone agent
pool), Unix milliseconds (local dispatcher), and Unix nanoseconds (the
older NATS path). The React AgentChat handler passed data.timestamp
straight through, so the standalone string and any numeric value outside
the millisecond range rendered as "Invalid Timestamp" or a constant
epoch-ish time.

Add a small pure helper, normalizeTimestampMs, that accepts an RFC3339
string or a numeric epoch in s/ms/us/ns and returns JS milliseconds,
falling back to Date.now() on null/empty/unparseable input. Use it in
the json_message handler so the rendered time is correct regardless of
which backend path produced it.

Fixes #9867

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

core/http/react-ui/src/pages/AgentChat.jsx

@@ -8,7 +8,7 @@ import CanvasPanel from '../components/CanvasPanel'
 import ResourceCards from '../components/ResourceCards'
 import ConfirmDialog from '../components/ConfirmDialog'
 import { useAgentChat } from '../hooks/useAgentChat'
-import { relativeTime } from '../utils/format'
+import { relativeTime, normalizeTimestampMs } from '../utils/format'
 import { copyToClipboard } from '../utils/clipboard'
 
 function getLastMessagePreview(conv) {
@@ -139,8 +139,9 @@ export default function AgentChat() {
           id: nextId(),
           sender,
           content: data.content || data.message || '',
-          // Backend sends Unix milliseconds (see core/services/agents events).
-          timestamp: data.timestamp || Date.now(),
+          // Backend timestamp encoding varies by deploy mode (RFC3339 string,
+          // Unix ms, or Unix ns); normalize to JS milliseconds.
+          timestamp: normalizeTimestampMs(data.timestamp),
         }
         if (data.metadata && Object.keys(data.metadata).length > 0) {
           msg.metadata = data.metadata

core/http/react-ui/src/utils/format.js

@@ -12,6 +12,26 @@ export function percentColor(pct) {
   return 'var(--color-success)'
 }
 
+// normalizeTimestampMs converts a timestamp emitted by the backend into JS
+// milliseconds, regardless of its encoding. The agent SSE bridge emits the
+// json_message timestamp in three different shapes depending on deploy mode:
+// an RFC3339 string (standalone agent pool), Unix milliseconds (local
+// dispatcher), or Unix nanoseconds (older NATS path). A numeric value is
+// classified by magnitude (s / ms / us / ns) so any of them yields a sane
+// epoch. Falls back to Date.now() for null/empty/unparseable input.
+export function normalizeTimestampMs(ts) {
+  if (ts === null || ts === undefined || ts === '') return Date.now()
+  if (typeof ts === 'string') {
+    const parsed = Date.parse(ts)
+    return Number.isNaN(parsed) ? Date.now() : parsed
+  }
+  if (typeof ts !== 'number' || !Number.isFinite(ts)) return Date.now()
+  if (ts > 1e17) return Math.floor(ts / 1e6) // nanoseconds
+  if (ts > 1e14) return Math.floor(ts / 1e3) // microseconds
+  if (ts > 1e11) return ts                    // milliseconds
+  return ts * 1000                            // seconds
+}
+
 export function formatTimestamp(ts) {
   if (!ts) return '-'
   const d = new Date(ts)