[WIP] Docker Compose setup for local development

[y4ssi]

This work-in-progress PR adds a docker-compose.yml to support local development and testing of the Zallet project.

What's Included

• Zallet service built from local Dockerfile

  • Uses the local Dockerfile to build the Zallet binary into a minimal image.
  • Mounts local configuration (zallet.toml) and wallet data.

• Optional init-rage service for first-run identity setup

  • Alpine-based one-shot container that installs rage and generates identity.txt if it doesn't exist.
  • Shared volume (./zallet_data) allows the result to persist across runs.
  • Can be run manually, or automatically if included in the Compose profile.

Notes

• The docker-compose.yml is intended for local use only (not production).
• init-rage is optional and can be triggered manually via:

  docker compose run --rm init-rage