fix(web): grant turn-tail IconActions only after the turn ends

`assistantActionsSeqs` picked the last content-text assistant of each turn
from the finalized transcript alone. That quantity is stable only once the
turn closes: while a turn is still producing steps, the narration written
before a tool call is the last content assistant so far, so copy, branch,
and the clock appeared under an intermediate sentence for as long as the
tool ran and then moved down to the next step's text.

Pass `ConversationSnapshot.turnEnds` into the derivation and grant the row
only inside a turn that has a durable `turn/end`. This is the same
completion fact the branch control and the `Ran for` label already read, so
the three parts of one row now agree; mid-turn narration owns nothing, and
the seat appears once under the settled answer.

`hasContentText` moves to chat-flow.ts so the ownership gate and
AssistantMarkdown's mount gate cannot drift apart.

apps/web/tests/turn-tail-actions.e2e.ts pins both states through the
assembled application: a hang sidecar on the second model call parks a turn
whose first step narrated before calling bash, and the two goldens hold the
parked flow and the flow after stopping.

packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx

@@ -4,10 +4,10 @@
 // view groups them into tool rows through its keyed toolview slot (figma
 // step-summary flow). Shared by finalized nodes and the streaming partial;
 // the turn-level loading dots live in the chat view's tail, not here.
-// Finalized content (text) nodes append IconActions once streaming ends
-// (`time` is omitted for mid-turn narration); their branch action is enabled
-// only when the node is also the completed turn's transcript tail. Think /
-// tool-head-only nodes stay chrome-free.
+// Finalized content (text) nodes append IconActions once their turn ends
+// (`time` is omitted for mid-turn narration and while the turn still runs);
+// their branch action is enabled only when the node is also the completed
+// turn's transcript tail. Think / tool-head-only nodes stay chrome-free.
 
 import { memo, useMemo } from 'react'
 import type { AssistantBlock } from '@deepseek-ai/dsh-client-runtime/client'
@@ -15,6 +15,7 @@ import {
   IconThinkOutline14, JsonBlock, MarkdownText,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { ChatViewSlotProps } from '../contract/slots.ts'
+import { hasContentText } from './chat-flow.ts'
 import { MessageIconActions } from './MessageIconActions.tsx'
 import { ToolRow } from './ToolRow.tsx'
 import css from './AssistantMarkdown.module.css'
@@ -25,7 +26,8 @@ export interface AssistantMarkdownProps {
   /** Frozen partial of an aborted turn: rendered with a stopped marker. */
   interrupted?: boolean | undefined
   /** Unix epoch ms for the IconActions clock; omitted while streaming or when
-   *  the parent withholds chrome (mid-turn content assistants). */
+   *  the parent withholds chrome (mid-turn content assistants and every node
+   *  of a turn that has not ended). */
   time?: number | undefined
   /** Turn wall time in ms for the IconActions run-time label; omitted when the
    *  turn's triggering input is outside the loaded window. */
@@ -65,11 +67,6 @@ function copyText(blocks: readonly AssistantBlock[]): string {
   return parts.join('')
 }
 
-/** True when the node has model-visible text content worth chrome under. */
-function hasContentText(blocks: readonly AssistantBlock[]): boolean {
-  return blocks.some(block => block.kind === 'text' && block.text.trim() !== '')
-}
-
 /** Reasoning block as the Think variant summary row (figma 39:28304). */
 function ThinkRow({ text, running, t }: { text: string; running: boolean; t: AssistantMarkdownProps['t'] }) {
   return (

packages/client/ui-conversation/src/client/chat/ChatView.tsx

@@ -358,9 +358,10 @@ export function ChatView({
     [inbox],
   )
   const activeRetry = useMemo(() => activeRetrySeq(nodes, running), [nodes, running])
-  // Only the last content assistant of each turn owns IconActions; mid-turn
-  // text (before tools) omits `time` so AssistantMarkdown stays chrome-free.
-  const actionSeqs = useMemo(() => assistantActionsSeqs(nodes), [nodes])
+  // Only the last content assistant of each completed turn owns IconActions;
+  // mid-turn text and every node of a running turn omit `time`, so
+  // AssistantMarkdown stays chrome-free until the answer settles.
+  const actionSeqs = useMemo(() => assistantActionsSeqs(nodes, turnEnds), [nodes, turnEnds])
   const branchSeqs = useMemo(() => messageBranchSeqs(nodes, turnEnds), [nodes, turnEnds])
   const runningTurnStart = useMemo(() => runningTurnStartTime(turnTimings), [turnTimings])
   const turnMetrics = useMemo(() => deriveTurnMetrics(nodes), [nodes])

packages/client/ui-conversation/src/client/chat/chat-flow.ts

@@ -17,8 +17,14 @@ export type ChatFlowItem =
   | { kind: 'node'; key: string; node: ConversationNode }
   | { kind: 'tool-group'; key: string; results: readonly ToolResultNode[] }
 
-/** True when the node has model-visible text content worth IconActions chrome. */
-function hasContentText(blocks: readonly AssistantBlock[]): boolean {
+/**
+ * True when the node has model-visible text content worth IconActions chrome.
+ * Shared with {@link AssistantMarkdown}'s mount gate so ownership and mounting
+ * cannot diverge.
+ * @param blocks - assistant blocks of one finalized node.
+ * @returns Whether any text block carries non-blank content.
+ */
+export function hasContentText(blocks: readonly AssistantBlock[]): boolean {
   return blocks.some(block => block.kind === 'text' && block.text.trim() !== '')
 }
 
@@ -34,14 +40,20 @@ function rendersNothing(node: ConversationNode): boolean {
 
 /**
  * Seq set of assistants that own IconActions: the last content-text assistant
- * in each turn. Mid-turn narration (text before tools) stays chrome-free.
+ * of each *completed* turn. A turn without a `turn/end` in the window is still
+ * producing steps, so its latest narration is not the settled answer and owns
+ * nothing; mid-turn narration of a completed turn stays chrome-free too.
  * @param nodes - snapshot nodes (surface order).
+ * @param turnEnds - completed turn boundaries retained from the event window.
  * @returns Seq values ChatView may pass as `time` into AssistantMarkdown.
  */
-export function assistantActionsSeqs(nodes: readonly ConversationNode[]): ReadonlySet<number> {
+export function assistantActionsSeqs(
+  nodes: readonly ConversationNode[],
+  turnEnds: ReadonlyMap<number, number>,
+): ReadonlySet<number> {
   const lastByTurn = new Map<number, number>()
   for (const node of nodes) {
-    if (node.kind !== 'assistant' || !hasContentText(node.blocks)) continue
+    if (node.kind !== 'assistant' || !turnEnds.has(node.turn) || !hasContentText(node.blocks)) continue
     lastByTurn.set(node.turn, node.seq)
   }
   return new Set(lastByTurn.values())