refactor(host)!: retire the skill.invoke RPC for the gesture boundary

Invocation is an ordinary session.prompt again: the pre-step gesture
boundary makes it deterministic host-side for every front end, so the
dedicated RPC (handler, wire schema, error codes, client face, fixtures)
and ui-skill's claim machinery are net deletions. The menu keeps decision
21 exactly — a pick lands literal /name text — plus the user-only marker
from skill.list's modelInvocable flag.

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

@@ -24,7 +24,6 @@
 import {
   memo, useEffect, useLayoutEffect, useMemo, useRef, useState, type ReactNode,
 } from 'react'
-import { opensUserTurn } from '@deepseek-ai/dsh-client-runtime/client'
 import type {
   CodeSubCall, CommandNode, ConversationNode, ConversationSnapshot, RunningToolCall, ToolResultNode,
 } from '@deepseek-ai/dsh-client-runtime/client'
@@ -119,7 +118,7 @@ function activeRetrySeq(nodes: readonly ConversationNode[], running: boolean): n
     const node = nodes[index]
     if (node === undefined) continue
     if (node.kind === 'model-retry') return node.retryState === 'cancelled' ? null : node.seq
-    if (node.kind === 'assistant' || opensUserTurn(node)) return null
+    if (node.kind === 'assistant' || node.kind === 'user') return null
   }
   return null
 }
@@ -448,11 +447,10 @@ export function ChatView({
       return
     }
     firstSeqRef.current = firstSeq
-    // Own words must be visible: a new trailing user-turn node (a prompt or an
-    // explicit skill invocation) force-scrolls (send lives in the composer, so
-    // arrival is detected here, not armed there).
+    // Own words must be visible: a new trailing user node force-scrolls
+    // (send lives in the composer, so arrival is detected here, not armed there).
     const appendedUser = lastKey !== lastKeyRef.current
-      && lastItem !== undefined && lastItem.kind === 'node' && opensUserTurn(lastItem.node)
+      && lastItem !== undefined && lastItem.kind === 'node' && lastItem.node.kind === 'user'
     const appendedSteering = lastSteeringId !== null && lastSteeringId !== lastSteeringIdRef.current
     const tipMoved = followSigRef.current !== followSig
     lastKeyRef.current = lastKey

packages/client/ui-conversation/src/client/chat/MessageItem.module.css

@@ -256,30 +256,3 @@
   white-space: nowrap;
   vertical-align: baseline;
 }
-
-/* User-explicit skill invocation: the injected body collapses behind a
-   disclosure inside the user bubble. */
-.skillInvocationDetails {
-  margin-top: 6px;
-}
-
-.skillInvocationSummary {
-  cursor: pointer;
-  font-size: 0.8em;
-  color: var(--dsw-alias-label-secondary);
-  user-select: none;
-}
-
-.skillInvocationBody {
-  margin: 6px 0 0;
-  padding: 8px;
-  max-height: 320px;
-  overflow: auto;
-  border-radius: 6px;
-  background: var(--dsw-alias-bg-secondary, rgba(0, 0, 0, 0.06));
-  font-family: var(--dsw-font-mono, monospace);
-  font-size: 0.78em;
-  line-height: 1.5;
-  white-space: pre-wrap;
-  word-break: break-word;
-}

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

@@ -7,8 +7,8 @@
 import { memo, useEffect, useMemo, useState } from 'react'
 import type { ReactNode } from 'react'
 import type {
-  CompactionSummaryNode, ContextMessageNode, ModelRetryNode, SkillInvocationNode,
-  SteeringMessageNode, TurnErrorNode, UnknownSurfaceNode, UserMessageNode,
+  CompactionSummaryNode, ContextMessageNode, ModelRetryNode, SteeringMessageNode,
+  TurnErrorNode, UnknownSurfaceNode, UserMessageNode,
 } from '@deepseek-ai/dsh-client-runtime/client'
 import { JsonBlock, MessageText, StateDot } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { ChatViewSlotProps } from '../contract/slots.ts'
@@ -22,7 +22,6 @@ export interface MessageItemProps {
     | UserMessageNode
     | SteeringMessageNode
     | ContextMessageNode
-    | SkillInvocationNode
     | CompactionSummaryNode
     | ModelRetryNode
     | TurnErrorNode
@@ -192,38 +191,6 @@ function UserStyleBubble({
   )
 }
 
-/**
- * A user-explicit skill invocation: the right-aligned bubble presents the
- * `/name args` gesture from source metadata (never re-parsed from the body),
- * and the injected `<skill_content>` collapses behind a disclosure — the
- * durable content is model-facing bulk, not conversation prose.
- */
-function SkillInvocationRow({ node, t }: {
-  node: SkillInvocationNode
-  t: ChatViewSlotProps['t']
-}): ReactNode {
-  const { text } = contentText(node.content)
-  return (
-    <div className={css.userRow} data-skill-invocation data-time-hover-root>
-      <div className={css.bubble}>
-        <span className={css.refChip} data-ref-chip="skill">{`/${node.name}`}</span>
-        {node.args !== undefined && <MessageText text={` ${node.args}`} />}
-        <details className={css.skillInvocationDetails}>
-          <summary className={css.skillInvocationSummary}>{t('message.skillInvocation.expand')}</summary>
-          <pre className={css.skillInvocationBody}>{text}</pre>
-        </details>
-      </div>
-      <MessageIconActions
-        text={text}
-        time={node.time}
-        clock="start"
-        className={css.actions}
-        t={t}
-      />
-    </div>
-  )
-}
-
 /**
  * Render one Host-authoritative pending steering item with the same visual
  * language as its eventual durable transcript node.
@@ -285,8 +252,6 @@ export const MessageItem = memo(function MessageItem({
           t={t}
         />
       )
-    case 'skill-invocation':
-      return <SkillInvocationRow node={node} t={t} />
     case 'compaction':
       return <CompactionItem node={node} t={t} />
     case 'model-retry':

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

@@ -79,7 +79,6 @@ export const zh = {
   'message.context.recall.counts': '保留 {retained} 条 · 省略 {omitted} 条',
   'message.context.recall.truncated': '已截断',
   'message.steering': '插话',
-  'message.skillInvocation.expand': '查看注入的 skill 内容',
   'message.compaction': '上下文已压缩',
   'message.compaction.expand': '点击查看压缩摘要',
   'message.compaction.unavailable': '压缩摘要不可用',
@@ -220,7 +219,6 @@ export const en = {
   'message.context.recall.counts': '{retained} kept · {omitted} omitted',
   'message.context.recall.truncated': 'truncated',
   'message.steering': 'Interjection',
-  'message.skillInvocation.expand': 'View injected skill content',
   'message.compaction': 'Context compacted',
   'message.compaction.expand': 'View compaction summary',
   'message.compaction.unavailable': 'Compaction summary unavailable',