feat(api-gateway): admin 路由组 + BFF 路径重写 + announcements 路由 + Dockerfile 修复 + nextstep v2 文档

services/api-gateway/Dockerfile

@@ -1,26 +1,37 @@
 # 多阶段构建：api-gateway 生产镜像
 # 用法：docker build -t edu/api-gateway:latest -f services/api-gateway/Dockerfile .
+# 构建上下文必须是仓库根目录（需访问 packages/shared-go 与 go.work）
 
 # ============ Builder ============
 FROM golang:1.25-alpine AS builder
 WORKDIR /app
 
+# 使用国内 Go 模块代理（容器内无法访问 proxy.golang.org）
+ENV GOPROXY=https://goproxy.cn,direct
+ENV GOSUMDB=off
+
 # git 与 ca-certificates 为 go mod 下载所需
 RUN apk add --no-cache git ca-certificates
 
-# 先拷依赖清单利用缓存（shared-go + api-gateway）
-COPY packages/shared-go/go.mod ./packages/shared-go/
+# 利用 go.work 时需拷贝根 go.work 与 shared-go 包
+# 注意：go.work 引用了 push-gateway，但本构建仅需要 api-gateway + shared-go，
+# 故生成精简版 go.work 避免加载缺失模块
+COPY go.work.sum ./
+COPY packages/shared-go ./packages/shared-go
 COPY services/api-gateway/go.mod services/api-gateway/go.sum ./services/api-gateway/
-ENV GOPROXY=https://goproxy.cn,direct
+# 生成仅含 api-gateway + shared-go 的精简 go.work
+RUN printf 'go 1.25.0\n\nuse (\n  ./packages/shared-go\n  ./services/api-gateway\n)\n' > go.work
 RUN cd services/api-gateway && go mod download
 
 # 拷源码并构建
 COPY services/api-gateway ./services/api-gateway
 COPY packages/shared-go ./packages/shared-go
-RUN cd services/api-gateway && CGO_ENABLED=0 GOOS=linux go build \
-    -ldflags="-s -w" \
+# 静态编译，CGO_DISABLED 便于 alpine 运行
+# 注入 version 便于可观测性资源属性
+RUN CGO_ENABLED=0 GOOS=linux go build \
+    -ldflags="-s -w -X main.version=docker" \
     -o /app/bin/api-gateway \
-    ./main.go
+    ./services/api-gateway
 
 # ============ Runtime ============
 FROM alpine:3.20 AS runner