feat: Matrix AI voice agent (LiveKit + LiteLLM)

Bot @ai:agiliton.eu accepts room invites, dispatches LiveKit agent.
Agent joins call with STT (Groq Whisper) → LLM (Sonnet) → TTS (ElevenLabs)
pipeline, all routed through LiteLLM.

CF-1147

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,6 @@
+FROM python:3.11-slim
+WORKDIR /app
+RUN apt-get update && apt-get install -y --no-install-recommends ffmpeg && rm -rf /var/lib/apt/lists/*
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+COPY . .