Decouple multi-platform builds from default docker-compose config

[d3mocide]

Summary

Refactors Docker build configuration to separate multi-platform (amd64 + arm64) builds from the default single-architecture workflow. This allows developers to build for their host architecture by default while providing an opt-in path for registry pushes that serve both x86 and Raspberry Pi deployments.

Changes

• New file: docker-compose.multiplatform.yml — Compose override file that adds platforms: [linux/amd64, linux/arm64] to all four service build configs (backend, poller, frontend, transcription). Includes usage instructions and buildx setup requirement.

• Modified: docker-compose.yml — Removed hardcoded platforms directives from all four services. This allows docker compose build to target the host architecture by default, improving build speed for local development.

• Modified: Makefile — Updated build targets:

  • build target now runs docker compose build without setup-buildx dependency (faster for local dev)
  • New build-multiplatform target runs setup-buildx then builds with the override file for registry pushes
  • Removed setup-buildx dependency from prod and dev targets (no longer needed for single-arch builds)

Implementation Details

The multi-platform override pattern follows Docker Compose best practices: the base docker-compose.yml defines the core service structure, and docker-compose.multiplatform.yml layers platform-specific build directives on top. This is invoked via:

docker compose -f docker-compose.yml -f docker-compose.multiplatform.yml build

Or via the convenience target:

make build-multiplatform

The setup-buildx target (which registers QEMU binfmt handlers) is now only required when explicitly building multi-platform images, not for routine development or production startup.

https://claude.ai/code/session_011q11kw1s43qRJM8DYZjyHx