build: add Docker packaging for rkn-check CLI

Dockerfile

@@ -9,11 +9,14 @@ RUN apt-get update \
     && apt-get install -y --no-install-recommends ca-certificates \
     && rm -rf /var/lib/apt/lists/*
 
-COPY requirements.txt .
+COPY pyproject.toml requirements.txt ./
 RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
-RUN pip install --no-cache-dir .
+RUN pip install --no-cache-dir --no-deps .
+
+RUN useradd --create-home --shell /bin/bash rkncheck
+USER rkncheck
 
 ENTRYPOINT ["rkn-check"]
 CMD ["--help"]

README.md

@@ -86,40 +86,6 @@ pip install -e .
 rkn-check
 ```
 
-## Run with Docker
-
-Build the image:
-
-```bash
-docker build -t rkn-block-checker .
-```
-
-Show CLI help:
-
-```bash
-docker run --rm rkn-block-checker
-```
-
-Run a real check:
-
-```bash
-docker run --rm rkn-block-checker --json
-```
-
-Use custom target lists from the current directory:
-
-```bash
-docker run --rm -v "$PWD:/work" -w /work rkn-block-checker \
-  --white-file ./whitelist.txt \
-  --black-file ./blacklist.txt
-```
-
-With Docker Compose:
-
-```bash
-docker compose run --rm rkn-check --json
-```
-
 ## Usage
 
 ```text