Updated Docker runtime to Elixir 1.20.1, Erlang/OTP 29.0.2, and Debian Trixie

This release upgrades the Docker image base to Elixir 1.20.1, Erlang/OTP 29.0.2, and Debian Trixie. Users who self-host or run the provided container benefit from the updated runtime dependencies, and the pinned tool versions in the project match the new image.