fix: 오디오 테스트를 실시간 레벨 미터로 개선

단발성 평균값 → 100ms 간격 실시간 RMS 스트리밍.
AudioCaptureService 직접 시작/5초 자동 중지.
테스트 버튼 누르면 레벨 바가 왔다갔다 반응.

src/main/ipc/audio-handlers.ts

@@ -3,10 +3,37 @@
 import { ipcMain } from 'electron'
 import { IPC_CHANNELS } from '@shared/ipc-channels'
 import { ipcSuccess, ipcError, ErrorCode } from '@shared/errors'
-import { getAudioCaptureService } from '../services/AudioCaptureService'
+import { getAudioCaptureService, calculateRMS } from '../services/AudioCaptureService'
+import { getMainWindow } from '../windows/WindowManager'
 import { configGet, configSet } from '../services/ConfigService'
+import { getLogger } from '../services/LoggerService'
 import type { SetDeviceParams } from '@shared/types'
 
+const logger = getLogger('audio-handlers')
+
+let testTimer: ReturnType<typeof setTimeout> | null = null
+let testAudioHandler: ((payload: { buffer: Buffer; timestamp: number }) => void) | null = null
+let testLevelInterval: ReturnType<typeof setInterval> | null = null
+let testLastRms = 0
+
+function stopAudioTest(): void {
+  const service = getAudioCaptureService()
+  if (testAudioHandler) {
+    service.off('audio-data', testAudioHandler)
+    testAudioHandler = null
+  }
+  if (testLevelInterval) {
+    clearInterval(testLevelInterval)
+    testLevelInterval = null
+  }
+  if (testTimer) {
+    clearTimeout(testTimer)
+    testTimer = null
+  }
+  testLastRms = 0
+  service.stop().catch(() => { /* ignore */ })
+}
+
 export function registerAudioHandlers(): void {
   ipcMain.handle(IPC_CHANNELS.AUDIO.GET_DEVICES, async () => {
     try {
@@ -32,10 +59,39 @@ export function registerAudioHandlers(): void {
 
   ipcMain.handle(IPC_CHANNELS.AUDIO.TEST_DEVICE, async () => {
     try {
+      // 이전 테스트가 진행 중이면 정리
+      stopAudioTest()
+
       const service = getAudioCaptureService()
-      const result = await service.testCapture(2000)
-      return ipcSuccess(result)
+      await service.start()
+
+      // 오디오 데이터에서 RMS 추적
+      testAudioHandler = (payload: { buffer: Buffer; timestamp: number }) => {
+        testLastRms = calculateRMS(payload.buffer)
+      }
+      service.on('audio-data', testAudioHandler)
+
+      // 100ms 간격으로 레벨을 렌더러에 전송
+      testLevelInterval = setInterval(() => {
+        const level = testLastRms > 0 ? Math.min(1.0, Math.pow(testLastRms, 0.28)) : 0
+        const win = getMainWindow()
+        if (win && !win.isDestroyed()) {
+          win.webContents.send('audio:testLevel', { level })
+        }
+      }, 100)
+
+      // 5초 후 자동 중지
+      testTimer = setTimeout(() => {
+        stopAudioTest()
+        const win = getMainWindow()
+        if (win && !win.isDestroyed()) {
+          win.webContents.send('audio:testLevel', { level: 0 })
+        }
+      }, 5000)
+
+      return ipcSuccess({ averageLevel: 0, peakLevel: 0, hasAudio: true })
     } catch (err) {
+      stopAudioTest()
       return ipcError(
         ErrorCode.AudioDeviceNotFound,
         `Audio test failed: ${err instanceof Error ? err.message : String(err)}`,