fix: use mautrix[encryption] instead of matrix-nio for Matrix bridge

The Hermes Matrix gateway uses the mautrix SDK, not matrix-nio.
This fixes E2EE support by installing the correct library.

Refs: PR #2

ai/compose.yml

@@ -30,7 +30,10 @@ services:
     container_name: hermes
     restart: always
     # Gateway run enables the internal API server on port 8642
-    command: gateway run
+    # Install openai and mautrix[encryption] for Matrix bridge with E2EE support on startup
+    # Uses uv (modern Python package manager) with --system flag for venv installation
+    entrypoint: >
+      sh -c "/opt/hermes/.venv/bin/uv pip install openai mautrix[encryption] --system -q && /opt/hermes/.venv/bin/hermes gateway run"
     environment:
       - OLLAMA_HOST=http://ollama:11434
       - API_SERVER_ENABLED=true
@@ -41,6 +44,7 @@ services:
       - OPENROUTER_API_KEY=${OPENROUTER_API_KEY}
     volumes:
       - /mnt/HoardingCow_docker_data/Hermes/data:/opt/data
+      - /mnt/HoardingCow_docker_data/Hermes/venv:/opt/hermes/.venv
     devices:
       - /dev/kfd:/dev/kfd
       - /dev/dri:/dev/dri