VoiceServer: Silent TTS failure returns HTTP 200 on invalid voice_id

[hjbrandt]

Bug Description

When a custom voice_id is passed to the VoiceServer /notify endpoint and the ElevenLabs API rejects it (e.g., invalid or inaccessible voice ID), the server catches the error silently and returns HTTP 200 with {"status": "success"}.

The caller has no indication that audio generation failed. No sound plays, but the response looks successful.

Steps to Reproduce

1. Start the VoiceServer
2. Send a notification with an invalid voice_id:

   curl -X POST http://localhost:8888/notify \
     -H "Content-Type: application/json" \
     -d '{"message": "Test", "voice_id": "invalid_voice_id_here"}'

3. Observe: HTTP 200 returned, but no audio plays

Expected Behavior

The server should either:

• Retry with the default voice and succeed, OR
• Return an error HTTP response indicating TTS failed

Root Cause

In sendNotification(), the generateSpeech error is caught but not re-thrown. The function continues to the macOS notification display and the HTTP handler returns 200.

Proposed Fix

PR incoming with retry-with-default-voice fallback and proper error propagation.

[kaimagnus]

Fixed in commit 95d65cc. sendNotification() now returns { voicePlayed, voiceError } and the HTTP handler returns 502 with the error message when TTS fails (instead of silently returning 200). The response includes notification_sent: true so callers know the desktop notification still went through even if voice failed. Thanks for the clear bug report! 🙏