fix: voice status global store, per-view mic reactivity, single-voice preview

- Move voice status into settings store (voiceSttReady, voiceTtsReady),
  checked once at login and refreshed after admin model reload
- ChatView, BriefingView, DashboardChatInput now use computed refs from
  the store — mic buttons appear reactively without needing a page reload
- BriefingView: separate STT-only guard for mic PTT vs TTS-only guard for
  listen mode / speak buttons
- Add ▶ Preview button to Voice & Speed section in Settings for single-
  voice testing without enabling blend mode

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/BriefingView.vue

@@ -4,6 +4,7 @@ import { useBackgroundRefresh } from '@/composables/useBackgroundRefresh'
 import { useVoiceRecorder } from '@/composables/useVoiceRecorder'
 import { useVoiceAudio } from '@/composables/useVoiceAudio'
 import { useChatStore } from '@/stores/chat'
+import { useSettingsStore } from '@/stores/settings'
 import ChatMessage from '@/components/ChatMessage.vue'
 import WeatherCard from '@/components/WeatherCard.vue'
 import BriefingSetupWizard from '@/components/BriefingSetupWizard.vue'
@@ -17,7 +18,6 @@ import {
   postRssReaction,
   deleteRssReaction,
   getNewsItems,
-  getVoiceStatus,
   transcribeAudio,
   synthesiseSpeech,
   type BriefingConversation,
@@ -39,6 +39,7 @@ interface WeatherData {
 }
 
 const chatStore = useChatStore()
+const settingsStore = useSettingsStore()
 
 // Setup wizard
 const showWizard = ref(false)
@@ -230,7 +231,9 @@ function convLabel(c: BriefingConversation): string {
 }
 
 // ─── Voice ────────────────────────────────────────────────────────────────────
-const voiceEnabled = ref(false)
+// Mic PTT needs STT; listen/speak mode also needs TTS
+const voiceEnabled = computed(() => settingsStore.voiceSttReady)
+const voiceTtsEnabled = computed(() => settingsStore.voiceTtsReady)
 const listenMode = ref(false)
 const transcribing = ref(false)
 const synthesising = ref(false)
@@ -238,14 +241,6 @@ const synthesising = ref(false)
 const recorder = useVoiceRecorder()
 const audio = useVoiceAudio()
 
-// Check voice availability once on mount
-async function checkVoice() {
-  try {
-    const status = await getVoiceStatus()
-    voiceEnabled.value = status.enabled && status.stt && status.tts
-  } catch { /* voice feature absent */ }
-}
-
 // Read the latest assistant message aloud
 async function listenToLatest() {
   const lastAssistant = [...messages.value].reverse().find((m) => m.role === 'assistant')
@@ -254,7 +249,7 @@ async function listenToLatest() {
 }
 
 async function speakText(text: string) {
-  if (!voiceEnabled.value || synthesising.value) return
+  if (!voiceTtsEnabled.value || synthesising.value) return
   // Strip markdown for cleaner TTS output
   const plain = text
     .replace(/```[\s\S]*?```/g, '')
@@ -304,7 +299,7 @@ async function stopPtt() {
 
 // Auto-TTS when listen mode is on and streaming ends
 watch(() => chatStore.streaming, async (streaming) => {
-  if (!streaming && listenMode.value && voiceEnabled.value) {
+  if (!streaming && listenMode.value && voiceTtsEnabled.value) {
     // Small delay to let messages update after stream
     await new Promise((r) => setTimeout(r, 200))
     await listenToLatest()
@@ -348,7 +343,6 @@ useBackgroundRefresh(
 onMounted(async () => {
   await checkSetup()
   if (!showWizard.value) await loadAll()
-  checkVoice()
 })
 </script>
 
@@ -430,7 +424,7 @@ onMounted(async () => {
         <div v-if="isToday" class="briefing-input-bar">
           <!-- Listen toggle -->
           <button
-            v-if="voiceEnabled"
+            v-if="voiceTtsEnabled"
             class="btn-icon"
             :class="{ 'btn-icon-active': listenMode, 'btn-icon-busy': synthesising || audio.playing.value }"
             @click="listenMode ? (listenMode = false) : (listenMode = true, listenToLatest())"
@@ -446,7 +440,7 @@ onMounted(async () => {
           </button>
           <!-- Stop TTS playback -->
           <button
-            v-if="voiceEnabled && (synthesising || audio.playing.value)"
+            v-if="voiceTtsEnabled && (synthesising || audio.playing.value)"
             class="btn-icon btn-icon-danger"
             @click="audio.stop(); synthesising = false"
             title="Stop playback"