Add scheduler backend image workflow

Dockerfile

@@ -0,0 +1,40 @@
+FROM golang:1.24-alpine AS base
+
+WORKDIR /src
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+FROM base AS test
+RUN go test ./...
+
+FROM base AS builder
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /out/api ./cmd/api \
+    && CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /out/worker ./cmd/worker \
+    && CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o /out/seed-sample-job ./cmd/tools/seed-sample-job
+
+FROM alpine:3.20
+
+RUN addgroup -S app && adduser -S app -G app
+
+WORKDIR /app
+
+COPY --from=builder /out/api /app/api
+COPY --from=builder /out/worker /app/worker
+COPY --from=builder /out/seed-sample-job /app/seed-sample-job
+COPY job-config-list /app/job-config-list
+COPY docker-entrypoint.sh /app/docker-entrypoint.sh
+
+RUN chmod +x /app/api /app/worker /app/seed-sample-job /app/docker-entrypoint.sh \
+    && chown -R app:app /app
+
+USER app
+
+ENV HTTP_PORT=16811 \
+    WORKER_HTTP_PORT=16812
+
+EXPOSE 16811 16812
+
+ENTRYPOINT ["/app/docker-entrypoint.sh"]