merge: 管理端最小后台 + TOTP 双因素 [tsk_SCMtcGF4F434]

以 main 现有 cmd/server 设计为准(保留 probe + /v1 路由),叠加分支新增:internal/admin/ 自包含后台(session/2FA/IP 白名单/审计/模板)、internal/totp/ + cmd/adminctl/(TOTP + 管理员创建 CLI)、cmd/server/main.go 的 startAdminIfConfigured()(opt-in:ADMIN_SECRET_KEY+DB_DSN 才起)。统一 getenvDefault 命名;go.mod 取 HEAD + go mod tidy(x/term 提为直接依赖);admins 迁移与 main 既有 000008_provision 撞号,重排为 000009_admins。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/cmd/server/main.go

@@ -9,11 +9,13 @@ import (
 
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
-	"github.com/wangjia/pangolin/server/internal/redisutil"
-	"github.com/wangjia/pangolin/server/internal/scheduler/probe"
 
 	"github.com/wangjia/pangolin/server/api/gen"
+	"github.com/wangjia/pangolin/server/internal/admin"
+	"github.com/wangjia/pangolin/server/internal/db"
 	"github.com/wangjia/pangolin/server/internal/httpapi"
+	"github.com/wangjia/pangolin/server/internal/redisutil"
+	"github.com/wangjia/pangolin/server/internal/scheduler/probe"
 )
 
 func main() {
@@ -28,6 +30,10 @@ func main() {
 		}
 	}
 
+	// Admin backend (separate internal listener). Started only when explicitly
+	// configured so the public API can run on its own. See internal/admin.
+	startAdminIfConfigured()
+
 	r := chi.NewRouter()
 	r.Use(middleware.Logger)
 	r.Use(middleware.Recoverer)
@@ -77,6 +83,44 @@ func main() {
 	}
 }
 
+// startAdminIfConfigured launches the admin listener in a background goroutine
+// when ADMIN_SECRET_KEY and DB_DSN are present. The admin port binds an
+// internal address only (enforced by admin.FromEnv) and is fronted by an IP
+// allowlist + two-factor login.
+func startAdminIfConfigured() {
+	if os.Getenv("ADMIN_SECRET_KEY") == "" || os.Getenv("DB_DSN") == "" {
+		log.Printf("admin backend disabled (set DB_DSN and ADMIN_SECRET_KEY to enable)")
+		return
+	}
+	cfg, err := admin.FromEnv()
+	if err != nil {
+		log.Fatalf("admin config: %v", err)
+	}
+	database, err := db.Open(os.Getenv("DB_DSN"))
+	if err != nil {
+		log.Fatalf("admin db: %v", err)
+	}
+	rdb, err := redisutil.New(
+		getenvDefault("REDIS_ADDR", "127.0.0.1:6379"),
+		os.Getenv("REDIS_PASSWORD"), 0)
+	if err != nil {
+		log.Fatalf("admin redis: %v", err)
+	}
+
+	svc := admin.BuildServices(database, rdb, 5, cfg.LoginLockDuration)
+	handler, err := admin.NewHandler(cfg, database, rdb, svc, log.Default())
+	if err != nil {
+		log.Fatalf("admin handler: %v", err)
+	}
+
+	go func() {
+		log.Printf("admin backend listening on %s (internal only)", cfg.Listen)
+		if err := http.ListenAndServe(cfg.Listen, handler); err != nil {
+			log.Fatalf("admin server error: %v", err)
+		}
+	}()
+}
+
 func getenvDefault(key, def string) string {
 	if v := os.Getenv(key); v != "" {
 		return v