CI/CD hardening: lint, secret scan, coverage gate, auto CVE-fix PRs, GHCR + GitHub mirror publishing (#32)

- release changelog: commits rendered as description (link), divider lines dropped
- gitleaks secret scan and hadolint on every push/PR
- ruff lint/format gate (Python repos) with a pytest --cov-fail-under gate
- scheduled CRITICAL Trivy failures attempt an apk upgrade rebuild and open a follow-up PR if it clears the finding, instead of just failing red
- images also published to ghcr.io/djeex/<repo>
- a matching GitHub Release is created on the GitHub mirror, with a notice pointing back to this repo as the source of truth

Dockerfile

@@ -11,13 +11,20 @@ RUN pip install --no-cache-dir -r requirements.txt
 
 FROM base AS test
 
-RUN pip install --no-cache-dir pytest==9.1.1
+RUN pip install --no-cache-dir pytest==9.1.1 pytest-cov==7.1.0
 
 COPY pytest.ini /app/pytest.ini
 COPY /tests/ /app/tests/
 
 CMD ["pytest", "-v"]
 
+FROM base AS lint
+
+RUN pip install --no-cache-dir ruff==0.16.4
+COPY ruff.toml /app/ruff.toml
+COPY /tests/ /app/tests/
+RUN ruff check . && ruff format --check .
+
 FROM base
 
 RUN addgroup -g 911 nvbot && adduser -D -u 911 -G nvbot nvbot