Track session usage totals (#26644)

packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx

@@ -337,6 +337,7 @@ export function Prompt(props: PromptProps) {
 
   const usage = createMemo(() => {
     if (!props.sessionID) return
+    const session = sync.session.get(props.sessionID)
     const msg = sync.data.message[props.sessionID] ?? []
     const last = msg.findLast((item): item is AssistantMessage => item.role === "assistant" && item.tokens.output > 0)
     if (!last) return
@@ -347,7 +348,7 @@ export function Prompt(props: PromptProps) {
 
     const model = sync.data.provider.find((item) => item.id === last.providerID)?.models[last.modelID]
     const pct = model?.limit.context ? `${Math.round((tokens / model.limit.context) * 100)}%` : undefined
-    const cost = msg.reduce((sum, item) => sum + (item.role === "assistant" ? item.cost : 0), 0)
+    const cost = session?.cost ?? 0
     return {
       context: pct ? `${Locale.number(tokens)} (${pct})` : Locale.number(tokens),
       cost: cost > 0 ? money.format(cost) : undefined,