refactor(auth): modularize auth plugin with physical subpackages and decoupled services

backend/plugins/domain/auth/consts/consts.go

@@ -0,0 +1,44 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package consts defines constants, keys, and TTL values for the auth domain plugin.
+package consts
+
+import "time"
+
+// Session and Context Keys
+const (
+	UserNameKey     = "username"
+	UserIDKey       = "user_id"
+	UserObjKey      = "user_obj"
+	TokenAuthKey    = "token_auth"          // 标记当前请求是否通过 Access Token 鉴权
+	TokenAdminKey   = "token_admin"         // Access Token 本身是否具有管理员权限
+	SessionTokenKey = "oauth_session_token" //nolint:gosec // false positive: session state key
+	PasswordHashKey = "password_hash"
+	SystemUsername  = "system"
+)
+
+// OAuth State Cache Keys and Expirations
+const (
+	OAuthStateCacheKeyFormat     = "oauth:state:%s"
+	OAuthStateCacheKeyExpiration = 10 * time.Minute
+	OAuthStateLimitKeyFormat     = "oauth:state:limit:%s"
+	OAuthStateLimitMax           = 10
+)
+
+// OAuth Purpose Constants
+const (
+	OAuthPurposeLogin = "login"
+	OAuthPurposeBind  = "bind"
+)
+
+// Auth Source Types
+const (
+	AuthSourceTypeOIDC = "oidc"
+)
+
+// Cache TTLs
+const (
+	TokenCacheTTL = 5 * time.Minute
+	UserCacheTTL  = 5 * time.Minute
+)