fix(desktop): start voice on wake via a latched store, not a window event

Wake opened a fresh session but voice didn't start: the start intent was
a fire-once window CustomEvent, and the fresh-session remount tore down /
recreated the composer's subscription, so the deferred dispatch landed in
the gap and was lost.

Replace it with a latched nanostore ($voiceConversationStartRequest +
takeVoiceConversationStart): the controller sets it on wake.detected, and
the composer claims it once on (re)mount when the gateway is open, waiting
out any transient `disabled`. Drop the now-unused composer voice-start
window event.

apps/desktop/src/app/chat/composer/focus.ts

@@ -42,7 +42,6 @@ const INSERT_EVENT = 'hermes:composer-insert'
 const INSERT_REFS_EVENT = 'hermes:composer-insert-refs'
 const SUBMIT_EVENT = 'hermes:composer-submit'
 const VOICE_TOGGLE_EVENT = 'hermes:composer-voice-toggle'
-const VOICE_START_EVENT = 'hermes:composer-voice-start'
 
 interface SubmitDetail {
   target: ComposerTarget
@@ -151,14 +150,6 @@ export const requestVoiceToggle = (target: ComposerTarget | 'active' = 'active')
 export const onComposerVoiceToggleRequest = (handler: (target: ComposerTarget) => void) =>
   subscribe<{ target: ComposerTarget }>(VOICE_TOGGLE_EVENT, ({ target }) => handler(target))
 
-/** Explicitly START (never stop) the active composer's voice conversation —
- *  used by the "Hey Hermes" wake word so a fresh session begins back-and-forth
- *  voice without the toggle risking an immediate stop. */
-export const requestVoiceStart = () => dispatch<{ at: number }>(VOICE_START_EVENT, { at: Date.now() })
-
-export const onComposerVoiceStartRequest = (handler: () => void) =>
-  subscribe<{ at: number }>(VOICE_START_EVENT, () => handler())
-
 /**
  * Focus a composer input across React commit + browser focus restore.
  *

apps/desktop/src/app/chat/composer/hooks/use-composer-voice.ts

@@ -1,15 +1,17 @@
+import { useStore } from '@nanostores/react'
 import { useCallback, useEffect, useRef, useState } from 'react'
 
 import { useI18n } from '@/i18n'
 import { chatMessageText, collectUnspokenTurnSpeech } from '@/lib/chat-messages'
 import { triggerHaptic } from '@/lib/haptics'
+import { $voiceConversationStartRequest, takeVoiceConversationStart } from '@/store/composer'
 import { resetBrowseState } from '@/store/composer-input-history'
 import { $gateway } from '@/store/gateway'
 import { notifyError } from '@/store/notifications'
 import { $autoSpeakReplies, setAutoSpeakReplies } from '@/store/voice-prefs'
 
 import type { ComposerTarget } from '../focus'
-import { onComposerVoiceStartRequest, onComposerVoiceToggleRequest } from '../focus'
+import { onComposerVoiceToggleRequest } from '../focus'
 import { useComposerScope } from '../scope'
 import type { ChatBarProps } from '../types'
 
@@ -55,6 +57,7 @@ export function useComposerVoice({
   const { $messages } = useComposerScope()
   const [voiceConversationActive, setVoiceConversationActive] = useState(false)
   const lastSpokenIdRef = useRef<string | null>(null)
+  const voiceStartRequest = useStore($voiceConversationStartRequest)
 
   const { dictate, voiceActivityState, voiceStatus } = useVoiceRecorder({
     focusInput,
@@ -143,15 +146,16 @@ export function useComposerVoice({
     [target, toggleVoiceConversation]
   )
 
-  useEffect(
-    () =>
-      onComposerVoiceStartRequest(() => {
-        if (target === 'main' && !disabled && !voiceConversationActive) {
-          setVoiceConversationActive(true)
-        }
-      }),
-    [disabled, target, voiceConversationActive]
-  )
+  useEffect(() => {
+    if (
+      target === 'main' &&
+      !disabled &&
+      takeVoiceConversationStart(voiceStartRequest) &&
+      !voiceConversationActive
+    ) {
+      setVoiceConversationActive(true)
+    }
+  }, [disabled, target, voiceConversationActive, voiceStartRequest])
 
   const wakePausedRef = useRef(false)
   const resumeWakeIfPaused = useCallback(() => {

apps/desktop/src/app/desktop-controller.tsx

@@ -52,6 +52,7 @@ import {
   setPetOverlayScaleHandler,
   setPetOverlaySubmitHandler
 } from '../store/pet-overlay'
+import { requestVoiceConversationStart } from '../store/composer'
 import { $filePreviewTarget, $previewTarget, closeActiveRightRailTab } from '../store/preview'
 import {
   $activeGatewayProfile,
@@ -105,7 +106,7 @@ import { openUpdatesWindow, startUpdatePoller, stopUpdatePoller } from '../store
 import { isSecondaryWindow } from '../store/windows'
 
 import { ChatView } from './chat'
-import { requestComposerFocus, requestComposerInsert, requestVoiceStart } from './chat/composer/focus'
+import { requestComposerFocus, requestComposerInsert } from './chat/composer/focus'
 import { useComposerActions } from './chat/hooks/use-composer-actions'
 import {
   ChatPreviewRail,
@@ -746,7 +747,7 @@ export function DesktopController() {
     (event: Parameters<typeof handleDesktopGatewayEvent>[0]) => {
       if (event.type === 'wake.detected') {
         startFreshSessionDraft()
-        requestVoiceStart()
+        requestVoiceConversationStart()
         return
       }
       handleDesktopGatewayEvent(event)

apps/desktop/src/store/composer.ts

@@ -21,6 +21,25 @@ export const $composerDraft = atom('')
 export const $composerAttachments = atom<ComposerAttachment[]>([])
 export const $composerTerminalSelections = atom<Record<string, string>>({})
 
+// Latched because opening a fresh session may remount the main composer before
+// it can start voice. Session-tile composers deliberately never consume this.
+export const $voiceConversationStartRequest = atom(0)
+let nextVoiceStartRequest = 0
+let handledVoiceStartRequest = 0
+
+export const requestVoiceConversationStart = (): void =>
+  $voiceConversationStartRequest.set(++nextVoiceStartRequest)
+
+export const takeVoiceConversationStart = (current: number): boolean => {
+  if (current <= handledVoiceStartRequest) {
+    return false
+  }
+
+  handledVoiceStartRequest = current
+
+  return true
+}
+
 // ---------------------------------------------------------------------------
 // Composer scopes — one live attachment set PER MOUNTED COMPOSER. The main
 // chat's scope wraps the module-level atom above (all existing readers keep