fix(web): make plan transitions admission-safe

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

@@ -89,7 +89,7 @@ export function apply(ctx: Context): void {
           subscribe: fn => slots.subscribe('conversation.view', fn),
           version: () => slots.getVersion('conversation.view'),
         },
-        send: (text, mode) => {
+        send: async (text, mode) => {
           const trimmed = text.trim()
           if (trimmed === '') return
           // Optimistic clear with failure restore (choreography lives with the
@@ -97,7 +97,12 @@ export function apply(ctx: Context): void {
           // The store write path stays inside the declared actions set:
           // restoreDraft itself no-ops once the user typed something new.
           actions.clearDraft()
-          void scoped.send(trimmed, mode).catch(() => { actions.restoreDraft(trimmed) })
+          try {
+            await scoped.send(trimmed, mode)
+          } catch (error: unknown) {
+            actions.restoreDraft(trimmed)
+            throw error
+          }
         },
         stop: () => {
           scoped.cancel().catch(() => {

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

@@ -112,8 +112,8 @@ export interface ConversationInjected {
     subscribe(fn: () => void): () => void
     version(): number
   }
-  /** Send choreography: trims, clears the draft optimistically, restores it on failure. */
-  send(text: string, mode: 'queue' | 'steer'): void
+  /** Send choreography through Host admission: trims, clears the draft optimistically, restores it on failure. */
+  send(text: string, mode: 'queue' | 'steer'): Promise<void>
   /** Cancel the in-flight turn (failure surfaces via snapshot.promptError). */
   stop(): void
   /** Navigate to another session (breadcrumb ancestors). */

packages/client/ui-conversation/src/client/skeleton/ConversationRoot.tsx

@@ -8,7 +8,7 @@
 // Breadcrumbs derive from useSessions with a pure parentId walk; the active
 // view id lives in the chat store's `view` field (per-session by store scope).
 
-import { useSyncExternalStore } from 'react'
+import { useEffect, useRef, useState, useSyncExternalStore } from 'react'
 import clsx from 'clsx'
 import { shallowEqual } from '@deepseek-ai/dsh-client-runtime/client'
 import type { SessionId, SessionListState, SessionSummary } from '@deepseek-ai/dsh-client-runtime/client'
@@ -54,11 +54,28 @@ export function ConversationRoot({
   const promptError = useSession(s => s.promptError)
   const turns = useSession(s => countTurns(s))
   const pending = useSession(s => s.pending)
+  const [submitting, setSubmitting] = useState(false)
+  const submittingRef = useRef(false)
+  const aliveRef = useRef(true)
+
+  useEffect(() => () => {
+    aliveRef.current = false
+  }, [])
 
   const error: InputBarError | null = promptError === null
     ? null
     : { op: promptError.op, message: `${promptError.error.message}（${promptError.error.code}）` }
   const controls = renderSlot('conversation.composer.controls', {})
+  const submit = (mode: 'queue' | 'steer'): void => {
+    if (submittingRef.current) return
+    submittingRef.current = true
+    setSubmitting(true)
+    const settle = (): void => {
+      submittingRef.current = false
+      if (aliveRef.current) setSubmitting(false)
+    }
+    void send(draft, mode).then(settle, settle)
+  }
 
   // The default composer doubles as the chain's all-decline fallback: a
   // pending wait with no registered takeover must still leave the input usable.
@@ -66,12 +83,13 @@ export function ConversationRoot({
     <InputBar
       draft={draft}
       running={running}
+      submitting={submitting}
       disabled={removed}
       error={error}
       variant="composer"
       controls={controls}
       onDraftChange={actions.setDraft}
-      onSend={(mode) => { send(draft, mode) }}
+      onSend={submit}
       onStop={stop}
     />
   )

packages/client/ui-conversation/src/client/skeleton/EmptyState.tsx

@@ -103,7 +103,8 @@ export function EmptyState({ useSessions, startSession }: EmptyStateProps) {
         <InputBar
           draft={draft}
           running={false}
-          disabled={sending}
+          submitting={sending}
+          disabled={false}
           error={error}
           variant="hero"
           placeholder="Message to run task, plan and build"

packages/client/ui-conversation/src/client/skeleton/InputBar.tsx

@@ -2,8 +2,8 @@
 // serves the empty state (variant='hero': centered launch card) and the
 // resident composer (variant='composer') — the empty→content transition is a
 // position move of this component, never a swap (layout ruling). Running
-// LOCKS the input: textarea disabled with the draft visible, stop is the only
-// action; the turn ending re-enables and refocuses.
+// LOCKS the input while Host admission or generation is active. Admission
+// settles before model work; running keeps Stop available until the turn ends.
 
 import { useEffect, useRef } from 'react'
 import type { KeyboardEvent, MouseEvent, ReactNode } from 'react'
@@ -19,6 +19,8 @@ export interface InputBarError {
 export interface InputBarProps {
   draft: string
   running: boolean
+  /** Prompt is waiting for selector settlement or synchronous Host admission. */
+  submitting: boolean
   disabled: boolean
   error: InputBarError | null
   /** Hero = empty-state centered card; composer = resident bottom bar. */
@@ -34,7 +36,7 @@ export interface InputBarProps {
 }
 
 export function InputBar({
-  draft, running, disabled, error, variant, placeholder, accessory, controls, onDraftChange, onSend, onStop,
+  draft, running, submitting, disabled, error, variant, placeholder, accessory, controls, onDraftChange, onSend, onStop,
 }: InputBarProps) {
   const empty = draft.trim() === ''
   const inputRef = useRef<HTMLTextAreaElement | null>(null)
@@ -52,7 +54,7 @@ export function InputBar({
 
   // Locked while running: the browser drops keystrokes AND focus on a disabled
   // textarea — no sending mid-turn, stop or wait.
-  const locked = disabled || running
+  const locked = disabled || running || submitting
 
   // Unlock (mount / session switch / turn end) returns focus to the box.
   useEffect(() => {
@@ -80,14 +82,14 @@ export function InputBar({
     inputRef.current?.focus()
   }
 
-  const primaryLabel = running ? '停止' : '发送'
+  const primaryLabel = running ? '停止' : submitting ? '发送中' : '发送'
   const onPrimary = (): void => {
     if (running) {
       onStop()
       return
     }
     /* v8 ignore next -- defensive: the primary button is disabled while empty||disabled, so a click cannot reach the false arm. */
-    if (!empty && !disabled) onSend('queue')
+    if (!empty && !disabled && !submitting) onSend('queue')
   }
 
   return (
@@ -108,7 +110,13 @@ export function InputBar({
             className={css.input}
             value={draft}
             disabled={locked}
-            placeholder={placeholder ?? (disabled ? '会话不可用' : running ? '回复生成中，可停止后再输入' : '输入消息，Enter 发送，Shift+Enter 换行')}
+            placeholder={placeholder ?? (disabled
+              ? '会话不可用'
+              : running
+                ? '回复生成中，可停止后再输入'
+                : submitting
+                  ? '正在发送…'
+                  : '输入消息，Enter 发送，Shift+Enter 换行')}
             rows={2}
             onChange={(e) => onDraftChange(e.target.value)}
             onKeyDown={onKeyDown}
@@ -123,8 +131,8 @@ export function InputBar({
             type="button"
             className={clsx(css.primary, running && css.stopping)}
             aria-label={primaryLabel}
-            title={running ? '停止本轮' : '发送（Enter）'}
-            disabled={!running && (empty || disabled)}
+            title={running ? '停止本轮' : submitting ? '正在等待发送确认' : '发送（Enter）'}
+            disabled={!running && (empty || disabled || submitting)}
             onMouseDown={keepFocus}
             onClick={onPrimary}
           >