feat: 新增 Docker 容器化部署，支持 Docker Hub 镜像发布

多阶段 Dockerfile、Compose、/health 探活与 JIANG13_* 环境变量；
entrypoint 自动修正 /data 卷权限，适配 1Panel 等平台；更新 README 部署文档。

Co-authored-by: Cursor <cursoragent@cursor.com>

Dockerfile

@@ -0,0 +1,55 @@
+# 姜十三论坛 — 多阶段构建：Node 前端 → Go 单二进制 → Alpine 运行镜像
+# 不使用 # syntax=docker/dockerfile:1，避免构建前额外拉取 docker.io/docker/dockerfile
+#
+# 国内网络：默认经 DaoCloud 拉取基础镜像，npm/go 走国内代理
+# 海外或已配置 Docker registry-mirrors 时可传空前缀：
+#   docker build --build-arg IMAGE_PREFIX= ...
+
+ARG IMAGE_PREFIX=docker.m.daocloud.io/library/
+ARG VERSION=dev
+
+# ── Stage 1: 前端构建（Vite → embed_static/static/spa）────────────────────
+FROM ${IMAGE_PREFIX}node:22-bookworm-slim AS frontend
+WORKDIR /src/frontend
+COPY frontend/package.json frontend/package-lock.json ./
+RUN npm config set registry https://registry.npmmirror.com \
+    && npm ci
+COPY frontend/ ./
+RUN npm run build
+
+# ── Stage 2: Go 编译（纯 Go SQLite，CGO_ENABLED=0）────────────────────────
+FROM ${IMAGE_PREFIX}golang:1.26-bookworm AS builder
+ARG VERSION
+ENV GOPROXY=https://goproxy.cn,direct
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+COPY --from=frontend /src/embed_static/static/spa ./embed_static/static/spa
+RUN CGO_ENABLED=0 go build -trimpath \
+    -ldflags "-s -w -X main.version=${VERSION}" \
+    -o /out/jiang13 ./cmd/jiang13
+
+# ── Stage 3: 运行镜像 ───────────────────────────────────────────────────────
+FROM ${IMAGE_PREFIX}alpine:3.21
+RUN sed -i 's/dl-cdn.alpinelinux.org/mirrors.aliyun.com/g' /etc/apk/repositories \
+    && apk add --no-cache ca-certificates tzdata wget su-exec \
+    && adduser -D -u 1000 -h /app jiang13
+
+ENV TZ=Asia/Shanghai
+
+WORKDIR /app
+COPY --from=builder /out/jiang13 /app/jiang13
+COPY docker-entrypoint.sh /docker-entrypoint.sh
+RUN chown jiang13:jiang13 /app/jiang13 \
+    && chmod +x /app/jiang13 /docker-entrypoint.sh
+
+# 以 root 启动，entrypoint 修正 /data 卷权限后 su-exec 降权为 jiang13
+VOLUME ["/data"]
+EXPOSE 3000
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
+    CMD wget -qO- http://127.0.0.1:3000/health || exit 1
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["--work-path", "/app", "--data", "/data", "--port", "3000"]