fix: harden live assistant interactions

frontend/src/hooks/useGeoAssistant.ts

@@ -20,6 +20,13 @@ interface UseGeoAssistantOptions {
   selectionBbox: VectorSelectionBBox | null
 }
 
+let assistantMessageSequence = 0
+
+function nextAssistantMessageId(role: AssistantChatMessage['role']): string {
+  assistantMessageSequence += 1
+  return `${role}-${Date.now()}-${assistantMessageSequence}`
+}
+
 export function useGeoAssistant({ selectedProjectId, selectedAreaId, selectionBbox }: UseGeoAssistantOptions) {
   const [status, setStatus] = useState<AssistantStatus | null>(null)
   const [models, setModels] = useState<AssistantModelRead[]>([])
@@ -68,7 +75,7 @@ export function useGeoAssistant({ selectedProjectId, selectedAreaId, selectionBb
   const ask = async (question: string): Promise<boolean> => {
     const trimmed = question.trim()
     if (!selectedProjectId || !trimmed || !selectedModel) return false
-    const userMessage: GeoAssistantMessage = { id: crypto.randomUUID(), role: 'user', content: trimmed }
+    const userMessage: GeoAssistantMessage = { id: nextAssistantMessageId('user'), role: 'user', content: trimmed }
     setMessages((current) => [...current, userMessage])
     setLoading(true)
     setError(null)
@@ -83,7 +90,7 @@ export function useGeoAssistant({ selectedProjectId, selectedAreaId, selectionBb
       })
       setMessages((current) => [
         ...current,
-        { id: crypto.randomUUID(), role: 'assistant', content: result.answer, response: result },
+        { id: nextAssistantMessageId('assistant'), role: 'assistant', content: result.answer, response: result },
       ])
       return true
     } catch (requestError) {