Unified the caption relay into a single SSE stream for both captions and TTS. Added support for forwarding late-arriving audio events through an event queue, included audio=true support, and made language selection mandatory when tts=1 is enabled.
Added support for selectable TTS voices in the relay. The selected voice is forwarded upstream as a query parameter, and the list of available voices is advertised to clients in the initial SSE connection event.
Added Text-to-Speech (TTS) support for spoken translations. When TTS is enabled, the original stage audio is muted, translated speech from SUSI is played, audio queue management was implemented, tts_url support was added, and interpretationTtsActive state was introduced.

Update interpretation to work with websockets as primary connection and sse as fallback
Prepare pr 19 for review