Add Docker support with Dockerfile, entrypoint script, and CI workflows

- Introduced a Dockerfile for building the application with Go and Node.js dependencies.
- Added a docker-entrypoint.sh script to manage container execution.
- Created a .dockerignore file to exclude unnecessary files from the Docker context.
- Updated Makefile to include a new target for building the Docker image.
- Added CI workflows for testing, formatting, and releasing artifacts in Gitea.

README.md

@@ -23,6 +23,60 @@ Without `--config`, built-in defaults are used.
 If you modify the web UI source (`web/ui`), rebuild frontend assets with:
 - `make build`
 
+## Docker
+
+Build the container image:
+
+- `make docker`
+- Default image tag: `scratchbox:dev`
+
+Optionally set a custom image name/tag:
+
+- `make docker DOCKER_IMAGE=scratchbox:latest`
+
+Run with persistent data and config directories:
+
+- `mkdir -p ./docker-data ./docker-config`
+- `docker run --rm -p 8080:8080 -v "$(pwd)/docker-data:/data" -v "$(pwd)/docker-config:/config" scratchbox:dev`
+
+Inside the container, the default command is:
+
+- `scratchbox server --config /config/config.yaml`
+
+Create config files with the image (writes to mounted `./docker-config`):
+
+- `docker run --rm -v "$(pwd)/docker-config:/config" scratchbox:dev generate-config > ./docker-config/config.yaml`
+- `docker run --rm -v "$(pwd)/docker-config:/config" scratchbox:dev generate-key > ./docker-config/config.key`
+
+## Release Artifacts
+
+Tagged releases provide `.tar.gz` archives with prebuilt Linux binaries.
+
+Variant guide:
+
+| Variant | Recommended for | Notes |
+| --- | --- | --- |
+| `default` | Most Linux distributions (Ubuntu, Debian, Fedora, Arch, etc.) | Smaller, dynamically linked Linux build |
+| `alpine-static` | Alpine Linux / musl-based environments | Statically linked for better compatibility |
+
+To unpack an artifact:
+
+- `tar -xzf scratchbox-<tag>-linux-amd64-default.tar.gz`
+
+To unpack into a specific directory:
+
+- `mkdir -p ./scratchbox-release`
+- `tar -xzf scratchbox-<tag>-linux-amd64-default.tar.gz -C ./scratchbox-release`
+
+To run from an unpacked artifact:
+
+- `./scratchbox-<os>-<arch>-<variant> server --config config.yaml`
+
+If you do not have a config file yet, generate one first:
+
+- `go run ./cmd/scratchbox generate-config > config.yaml`
+- `go run ./cmd/scratchbox generate-key > config.key`
+
 ## Configuration
 
 All configuration is YAML.