feat(p1): complete P1 foundation stage

- monorepo: pnpm workspace + go.work + pyproject.toml + commitlint/husky
- infra: docker-compose (minimal + full profiles) + init-sql + prometheus
- arch-scan: multi-language scanner skeleton (TS/Go/Python/Proto)
- shared-proto: buf v2 + classes.proto (ClassService CRUD contract)
- api-gateway: Go/Gin + JWT HS256 auth + reverse proxy + request ID
- classes: NestJS golden template (error system + observability + middleware + CRUD + tests)
- teacher-portal: Next.js + paper-feel UI design system
- CI/CD: 4 workflows (go/ts/py/proto)
- docs: migration guide + project_rules + coding-standards + git-workflow + ui-design-system + 004 + 9 module READMEs + known-issues + spec/plan migration + roadmap

services/api-gateway/internal/middleware/auth.go

@@ -0,0 +1,112 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/edu-cloud/api-gateway/internal/config"
+	"github.com/gin-gonic/gin"
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+)
+
+// AuthMiddleware 验证 JWT 并注入用户信息到请求头
+// P1 用 HS256，P2 改 RS256（IAM 签发）
+func AuthMiddleware(cfg *config.Config) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// 健康检查跳过鉴权
+		if c.Request.URL.Path == "/healthz" {
+			c.Next()
+			return
+		}
+
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"success": false,
+				"error": gin.H{
+					"code":    "UNAUTHORIZED",
+					"message": "missing authorization header",
+				},
+			})
+			return
+		}
+
+		tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
+		if tokenStr == authHeader {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"success": false,
+				"error": gin.H{
+					"code":    "UNAUTHORIZED",
+					"message": "invalid authorization scheme, expected Bearer",
+				},
+			})
+			return
+		}
+
+		token, err := jwt.Parse(tokenStr, func(t *jwt.Token) (interface{}, error) {
+			if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+				return nil, jwt.ErrSignatureInvalid
+			}
+			return []byte(cfg.JWTSecret), nil
+		})
+
+		if err != nil || !token.Valid {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"success": false,
+				"error": gin.H{
+					"code":    "INVALID_TOKEN",
+					"message": "token validation failed",
+				},
+			})
+			return
+		}
+
+		claims, ok := token.Claims.(jwt.MapClaims)
+		if !ok {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"success": false,
+				"error": gin.H{
+					"code":    "INVALID_CLAIMS",
+					"message": "invalid token claims",
+				},
+			})
+			return
+		}
+
+		// 注入用户信息到下游请求头
+		if sub, ok := claims["sub"].(string); ok {
+			c.Request.Header.Set("x-user-id", sub)
+		}
+		if roles, ok := claims["roles"].([]interface{}); ok {
+			roleStrs := make([]string, 0, len(roles))
+			for _, r := range roles {
+				if s, ok := r.(string); ok {
+					roleStrs = append(roleStrs, s)
+				}
+			}
+			c.Request.Header.Set("x-user-roles", strings.Join(roleStrs, ","))
+		}
+
+		c.Next()
+	}
+}
+
+// RequestIDMiddleware 注入请求 ID 用于全链路追踪
+func RequestIDMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		requestID := c.GetHeader("X-Request-ID")
+		if requestID == "" {
+			requestID = generateUUID()
+		}
+		c.Set("request_id", requestID)
+		c.Writer.Header().Set("X-Request-ID", requestID)
+		c.Next()
+	}
+}
+
+// generateUUID 生成带 req- 前缀的唯一请求 ID
+// 使用 uuid.New() 基于 RFC 4122 v4 随机 UUID，避免 time.Now() 产生的冲突与可预测性
+func generateUUID() string {
+	return "req-" + uuid.New().String()
+}