Initial commit: image registry structure and node-agent

Set up this repo as a base image registry. Each image is self-contained in
its own directory under images/ (Dockerfile + README.md + optional test.sh);
CI discovers them by glob, so adding an image needs no workflow changes.
template/ is the skeleton to copy.

The Makefile is the single entry point for both local work and CI, so a green
`make all` locally means a green pipeline.

Workflows:
  * lint.yaml  — layout check, hadolint, shellcheck
  * build.yaml — diffs against the base commit to build only the images that
    changed, smoke-tests each one before anything is published, then pushes.
    Releases are per-image tags (<image>/vX.Y.Z); main publishes :edge.

First image, node-agent: node:22-alpine plus a GNU userland (Alpine ships
BusyBox, whose applets take narrower flags than scripts and models expect),
helm, kubectl, jq, yq, bind-tools, curl, git, ripgrep, fd and friends.
Nothing is version-pinned — rebuilding is how upstream updates land, and the
published tag is what pins things for consumers.

Its smoke test asserts the deployment contract as well as tool presence: the
image must work non-root, with a read-only root filesystem and all
capabilities dropped, which is how ToolHive runs it.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

README.md

@@ -0,0 +1,73 @@
+# images
+
+Custom container images, published to the public
+[`rmcguire`](https://gitea.libretechconsulting.com/rmcguire/-/packages) registry
+on Gitea.
+
+Each image is self-contained in its own directory under `images/`: a `Dockerfile`,
+a `README.md`, and an optional `test.sh`.
+
+## Images
+
+| Image | Base | Purpose |
+| --- | --- | --- |
+| [`node-agent`](images/node-agent) | `node:22-alpine` | Node 22 plus a GNU shell, network and Kubernetes toolchain — a general-purpose command execution environment for AI agents |
+
+## Pulling
+
+```sh
+docker pull gitea.libretechconsulting.com/rmcguire/node-agent:latest
+```
+
+The registry is public, so no pull secret is required.
+
+## Tags
+
+| Tag | Points at |
+| --- | --- |
+| `vX.Y.Z` / `vX.Y` / `vX` | a released build |
+| `latest` | the most recent release |
+| `edge` | the current tip of `main` |
+| `main-<sha>` | one specific commit on `main` |
+
+Releases are cut per image by pushing a tag named `<image>/vX.Y.Z`, which builds
+and publishes that image alone:
+
+```sh
+git tag node-agent/v1.0.0 && git push origin node-agent/v1.0.0
+```
+
+Base images and package versions are deliberately **not** pinned — rebuilding is
+how upstream updates land, and the published tag is what pins things for whoever
+pulls it.
+
+## Adding an image
+
+```sh
+cp -r template images/my-image
+```
+
+1. Edit `images/my-image/Dockerfile`, or base it on an image already published
+   here (`FROM gitea.libretechconsulting.com/rmcguire/node-agent:latest`).
+2. Fill in `images/my-image/README.md`.
+3. Extend `images/my-image/test.sh` to assert whatever the image promises.
+4. `make build test IMAGE=my-image`
+
+CI needs no changes — it discovers every directory under `images/` that contains
+a `Dockerfile`.
+
+## Local development
+
+```sh
+make help                        # list targets
+make all                         # everything CI does
+make build test IMAGE=node-agent # one image
+```
+
+## CI
+
+Two Gitea workflows, both of which just call the `make` targets above:
+
+- **`lint.yaml`** — repository layout, `hadolint`, `shellcheck`.
+- **`build.yaml`** — builds only the images whose files changed, smoke-tests each
+  one before anything is published, then pushes on `main` or a release tag.