container-layer

# Container Layer Build a reproducible, cached environment overlay for ephemeral containers using a Dockerfile-like spec. ## Concept The container resets every session, but your environment shouldn't. This skill: 1. Parses a `Containerfile` (Dockerfile subset) that declares your environment 2. Caches the built result as a tarball in GitHub Releases 3. Restores from cache on subsequent boots (single fetch vs. N installs) 4. Provides a `uv` shim that captures ad-hoc installs back into the Containerfile ## Supported Containerfile Instructions ```dockerfile # Environment variables ENV KEY=value # Shell commands (including package installs) RUN apt-get install -y foo # system packages RUN uv pip install pandas numpy # Python packages (preferred) RUN pip install requests # also works # Fetch files from URLs or GitHub FETCH https://example.com/file.tar.gz /dest/path FETCH github:user/repo /dest/path # latest tarball FETCH github:user/repo@ref /dest/path # specific ref # Set working directory for subsequent RUN commands WORKDIR /some/path # Declare paths to include in the cached layer snapshot # (auto-detected for FETCH destinations and pip/uv installs) SNAPSHOT /additional/path/to/capture # Ignored (Dockerfile compat, no-op here): # FROM, EXPOSE, CMD, ENTRYPOINT, LABEL, ARG, VOLUME, USER, SHELL ``` ## Usage ### Single layer — build / restore ```python from scripts.containerfile import ContainerLayer layer = ContainerLayer( co...