feat(live-atc): route STT through local bridge with cloud fallback

app/composables/useLocalSpeechBridge.ts

@@ -3,6 +3,32 @@ import { ref } from 'vue'
 const PORTS = [8765, 8766, 8767, 8768, 8769, 8770]
 const HEALTH_TIMEOUT_MS = 1200
 const RECHECK_MS = 15_000
+const LOCAL_TIMEOUT_MS = 8000
+
+export async function postWithLocalFallback(
+  localUrl: string | null,
+  body: any,
+  cloudPost: () => Promise<any>,
+): Promise<any> {
+  if (localUrl) {
+    const ctrl = new AbortController()
+    const timeout = setTimeout(() => ctrl.abort(), LOCAL_TIMEOUT_MS)
+    try {
+      const response = await fetch(localUrl, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(body),
+        signal: ctrl.signal,
+      })
+      if (response.ok) return await response.json()
+    } catch {
+      // Local Bridge is unavailable: continue with the existing cloud path.
+    } finally {
+      clearTimeout(timeout)
+    }
+  }
+  return cloudPost()
+}
 
 export async function probeLocalSpeech(ports: number[] = PORTS): Promise<string | null> {
   for (const port of ports) {

app/composables/usePttRecording.localRouting.test.ts

@@ -0,0 +1,27 @@
+import { describe, it, expect, vi } from 'vitest'
+import { postWithLocalFallback } from './useLocalSpeechBridge'
+
+describe('postWithLocalFallback', () => {
+  it('uses local when it returns 2xx', async () => {
+    const local = vi.fn(async () => ({ ok: true, json: async () => ({ success: true, transcription: 'roger' }) }))
+    vi.stubGlobal('fetch', local as any)
+    const cloud = vi.fn()
+    const response = await postWithLocalFallback('http://127.0.0.1:8765/api/atc/ptt', { a: 1 }, cloud as any)
+    expect(response.transcription).toBe('roger')
+    expect(cloud).not.toHaveBeenCalled()
+  })
+
+  it('falls back to cloud when local throws', async () => {
+    vi.stubGlobal('fetch', vi.fn(async () => { throw new Error('refused') }) as any)
+    const cloud = vi.fn(async () => ({ success: true, transcription: 'cloud' }))
+    const response = await postWithLocalFallback('http://127.0.0.1:8765/api/atc/ptt', { a: 1 }, cloud as any)
+    expect(response.transcription).toBe('cloud')
+    expect(cloud).toHaveBeenCalledOnce()
+  })
+
+  it('falls back to cloud when localUrl is null', async () => {
+    const cloud = vi.fn(async () => ({ success: true, transcription: 'cloud' }))
+    const response = await postWithLocalFallback(null, { a: 1 }, cloud as any)
+    expect(response.transcription).toBe('cloud')
+  })
+})

app/composables/usePttRecording.ts

@@ -3,6 +3,7 @@ import { useApi } from '~/composables/useApi'
 import useCommunicationsEngine from '../../shared/utils/communicationsEngine'
 import { encodeWav } from '../../shared/utils/wavEncoder'
 import { pmLog } from '../../shared/utils/pmLog'
+import { postWithLocalFallback, useLocalSpeechBridge } from './useLocalSpeechBridge'
 
 export interface PttRecordingDeps {
   stopCurrentSpeech: () => void
@@ -24,6 +25,7 @@ export function usePttRecording(
 ) {
   const { currentState, variables: vars } = engine
   const api = useApi()
+  const { localUrl } = useLocalSpeechBridge()
   const {
     stopCurrentSpeech, speakWithRadioEffects, radioEffectsEnabled, inputMode,
     backendSessionId, backendExpectedPhrase, setLastTransmission, handlePilotTransmission,
@@ -278,13 +280,18 @@ export function usePttRecording(
       const base64Audio = arrayBufferToBase64(arrayBuffer)
 
       if (isIntercom) {
-        const result = await api.post('/api/atc/ptt', {
+        const payload = {
           audio: base64Audio,
           moduleId: 'pilot-monitoring-intercom',
           lessonId: 'intercom',
           format,
           sessionId: backendSessionId.value || undefined,
-        })
+        }
+        const result = await postWithLocalFallback(
+          localUrl('/api/atc/ptt'),
+          payload,
+          () => api.post('/api/atc/ptt', payload),
+        )
 
         if (result.success) {
           pmLog.info('PTT ✓ INTERCOM  transcription:', result.transcription)
@@ -300,14 +307,19 @@ export function usePttRecording(
           }
         }
       } else {
-        const result = await api.post('/api/atc/ptt', {
+        const payload = {
           audio: base64Audio,
           moduleId: 'pilot-monitoring',
           lessonId: currentState.value?.id || 'general',
           format,
           sessionId: backendSessionId.value || undefined,
           expected: buildSttExpected(),
-        })
+        }
+        const result = await postWithLocalFallback(
+          localUrl('/api/atc/ptt'),
+          payload,
+          () => api.post('/api/atc/ptt', payload),
+        )
 
         if (result.success) {
           pmLog.info('PTT ✓ RADIO  transcription:', result.transcription)