feat: traefik-selectel-dns — A-записи Selectel по роутам Traefik + CI сборка образа

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,22 @@
+# syntax=docker/dockerfile:1
+FROM golang:1.27-alpine AS build
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY cmd ./cmd
+COPY internal ./internal
+ARG VERSION=dev
+RUN CGO_ENABLED=0 GOOS=linux go build -trimpath \
+    -ldflags="-s -w -X main.version=${VERSION}" \
+    -o /out/traefik-selectel-dns ./cmd/traefik-selectel-dns
+
+# static: CA-сертификаты (для HTTPS к Selectel) + пользователь nonroot (uid 65532), без shell.
+# Для воспроизводимости закрепите образ по digest.
+FROM gcr.io/distroless/static-debian12:nonroot
+COPY --from=build /out/traefik-selectel-dns /traefik-selectel-dns
+USER 65532:65532
+EXPOSE 9090
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
+    CMD ["/traefik-selectel-dns", "-healthcheck"]
+ENTRYPOINT ["/traefik-selectel-dns"]
+CMD ["-config", "/etc/traefik-selectel-dns/config.yaml"]