fix(ci): bust DinD deps cache without full --no-cache rebuild

Full --no-cache exceeded runner time budget. Use DEPS_LOCK_ID build-arg
and fail-fast checks on requirements.txt instead.

.forgejo/workflows/image.yaml

@@ -62,7 +62,7 @@ jobs:
           export PATH="${HOME}/bin:${PATH}"
           echo "${REGISTRY_TOKEN}" | docker login "${REGISTRY}" -u "${REGISTRY_USER}" --password-stdin
           IMAGE="${REGISTRY}/${IMAGE_NAME}"
-          docker build --no-cache -f buildctx/Dockerfile.ci \
+          docker build --build-arg DEPS_LOCK_ID=2 -f buildctx/Dockerfile.ci \
             -t "${IMAGE}:latest" -t "${IMAGE}:main-${SHORT}" buildctx
           docker run --rm "${IMAGE}:main-${SHORT}" \
             /app/.venv/bin/python -c "import asyncpg; print('asyncpg ok')"