fix: use valid LiveKit development secret

docker-compose.yml

@@ -6,7 +6,7 @@ services:
     environment:
       LIVEKIT_URL: "http://localhost:7880"
       LIVEKIT_API_KEY: "${LIVEKIT_API_KEY:-devkey}"
-      LIVEKIT_API_SECRET: "${LIVEKIT_API_SECRET:-devsecret}"
+      LIVEKIT_API_SECRET: "${LIVEKIT_API_SECRET:-hopevoice-devsecret-2026-lan-only}"
       AZURE_SPEECH_KEY: "${AZURE_SPEECH_KEY:?Set AZURE_SPEECH_KEY in .env}"
       AZURE_SPEECH_REGION: "${AZURE_SPEECH_REGION:-eastus}"
       AZURE_TTS_VOICE: "${AZURE_TTS_VOICE:-en-US-Ava:DragonHDOmniLatestNeural}"