feat(M0): 工程地基 - Go API + Python 采集骨架 + CI + 数据契约

- api/: Go(chi) 只读 API 骨架, /healthz + 版本化路由(占位), Dockerfile, 单测
- ingestion/: Python 采集/ETL 包骨架, units 单位归一化(纯函数+测试), adapter 协议
- docker-compose.yml: postgres + redis + minio + api
- .github/workflows/ci.yml: Go build/vet/test + Python ruff/pytest
- docs/data-contract.md(两端共享契约) + docs/disclaimer.md(不提供购买声明)
- migrations/ 占位(M1 起填充)

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

api/cmd/server/main.go

@@ -0,0 +1,26 @@
+// Command server starts the OpenGoods public read-only API.
+package main
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/baicai2026-baicai/goods/api/internal/config"
+	"github.com/baicai2026-baicai/goods/api/internal/handler"
+)
+
+func main() {
+	cfg := config.Load()
+
+	srv := &http.Server{
+		Addr:              cfg.Addr,
+		Handler:           handler.Router(),
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+
+	log.Printf("OpenGoods API listening on %s", cfg.Addr)
+	if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		log.Fatalf("server error: %v", err)
+	}
+}