Add Sentry observability to the `agents`. Introduce a dedicated
`observability.py` module. Refactor both agents to use the shared
observability layer and extract task helpers into a new `tasks.py` module,
making task execution easier to instrument and maintain.
The multi-user transcriber service was not integrated into Docker Compose,
limiting its usability in local and development environments.
Add the necessary configuration to enable running and orchestrating the
multi-user transcriber via Compose.
leo