fix(client): route turn-tail through chain selector

packages/client/ui-conversation/src/client/apply.ts

@@ -303,7 +303,7 @@ export function apply(ctx: Context): void {
     children: {
       'conversation.chat.toolview': { kind: 'keyed', scope: 'session' },
       'conversation.chat.commandview': { kind: 'keyed', scope: 'session' },
-      'conversation.chat.turnTail': { kind: 'list', scope: 'session' },
+      'conversation.chat.turnTail': { kind: 'chain', scope: 'session' },
     },
     store: chatStore,
     inject: (sessionId: SessionId, actions: BoundActions<typeof chatStore>): ChatViewInjected => {

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

@@ -9,12 +9,13 @@
 // 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, type ReactNode } from 'react'
+import { memo, useMemo } from 'react'
 import type { AssistantBlock } from '@deepseek-ai/dsh-client-runtime/client'
+import type { PropsRenderSlots } from '@deepseek-ai/dsh-client-ui-slots'
 import {
   IconThinkOutline14, JsonBlock, MarkdownText,
 } from '@deepseek-ai/dsh-client-ui-primitives'
-import type { ChatViewSlotProps } from '../contract/slots.ts'
+import type { ChatViewSlotProps, TurnTailOwnerProps } from '../contract/slots.ts'
 import { hasContentText } from './chat-flow.ts'
 import { MessageIconActions } from './MessageIconActions.tsx'
 import { ToolRow } from './ToolRow.tsx'
@@ -40,9 +41,8 @@ export interface AssistantMarkdownProps {
   seq?: number | undefined
   /** Fork the session through this finalized message's completed turn when eligible. */
   onFork?: ((seq: number) => void) | undefined
-  /** Turn-tail content (the chat view's turnTail hole, rendered by the
-   *  owner); omitted for a mid-turn assistant. */
-  tail?: ReactNode | undefined
+  /** Turn-tail slot dispatch share and owner currency; omitted for a mid-turn assistant. */
+  turnTail?: (Pick<PropsRenderSlots<'conversation.chat.turnTail'>, 'renderSlotChain'> & { owner: TurnTailOwnerProps }) | undefined
   /** The message is not the transcript tail of a completed turn. */
   forkUnavailable?: boolean | undefined
   /** The owning view's locale seat, passed down as a plain prop. */
@@ -86,7 +86,7 @@ function ThinkRow({ text, running, t }: { text: string; running: boolean; t: Ass
 }
 
 export const AssistantMarkdown = memo(function AssistantMarkdown({
-  blocks, streaming, interrupted, time, runMs, ttftMs, tokensPerSecond, seq, onFork, forkUnavailable, tail, t,
+  blocks, streaming, interrupted, time, runMs, ttftMs, tokensPerSecond, seq, onFork, forkUnavailable, turnTail, t,
 }: AssistantMarkdownProps) {
   // Stable per locale revision (t identity changes on switch): a fresh object
   // per render would rebuild MarkdownText's component table every chunk.
@@ -124,7 +124,7 @@ export const AssistantMarkdown = memo(function AssistantMarkdown({
         })}
         {interrupted && <span className={css.stopped}>{t('message.stopped')}</span>}
       </div>
-      {showActions && tail}
+      {showActions && turnTail?.renderSlotChain('conversation.chat.turnTail', turnTail.owner)}
       {showActions && (
         <MessageIconActions
           text={copyText(blocks)}

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

@@ -335,7 +335,7 @@ function StreamingTail({ useSession, t }: {
  * render through the declared keyed hole's renderSlot share).
  */
 export function ChatView({
-  useSession, useSessions, useStore, renderSlot, sessionId, openFile, loadOlder, inspectCall, chatScroll, forkAt, t,
+  useSession, useSessions, useStore, renderSlot, renderSlotChain, sessionId, openFile, loadOlder, inspectCall, chatScroll, forkAt, t,
 }: ChatViewSlotProps) {
   const nodes = useSession(s => s.nodes)
   const turnTimings = useSession(s => s.turnTimings)
@@ -600,8 +600,8 @@ export function ChatView({
           seq={node.seq}
           onFork={forkAt}
           forkUnavailable={!branchSeqs.has(node.seq)}
-          tail={actionSeqs.has(node.seq)
-            ? renderSlot('conversation.chat.turnTail', { nodes, seq: node.seq, openFile })
+          turnTail={actionSeqs.has(node.seq)
+            ? { renderSlotChain, owner: { nodes, seq: node.seq, openFile } }
             : undefined}
           t={t}
         />

packages/client/ui-conversation/src/client/contract/slots.ts

@@ -47,14 +47,13 @@ declare module '@deepseek-ai/dsh-client-ui-slots' {
      */
     'conversation.chat.commandview': { kind: 'keyed'; scope: 'session'; owner: CommandRowOwnerProps }
     /**
-     * The chat view's turn-tail hole: rendered between a closing assistant
+     * The chat view's turn-tail chain: rendered between a closing assistant
      * message's body and its IconActions footer, once per turn (the render
-     * site elects the closing seq). Declared by the chat view entry; feature
-     * plugins (ui-deliverables' produced-files row) derive what they show
-     * from the owner currency, and an unregistered hole renders nothing —
-     * composing such a plugin out of cordis.yml turns its surface off.
+     * site elects the closing seq). Entries derive a match from the owner
+     * currency before mounting, so presentation components never mount only
+     * to return null; an all-declined chain renders nothing.
      */
-    'conversation.chat.turnTail': { kind: 'list'; scope: 'session'; owner: TurnTailOwnerProps }
+    'conversation.chat.turnTail': { kind: 'chain'; scope: 'session'; owner: TurnTailOwnerProps }
     /**
      * The composer takeover chain: entries are selector-routed replacements
      * of the default InputBar. Declared by this package's 'conversation'