fix(security): resolve FLAW-08 with token_version invalidation and jwt blacklist

internal/auth/auth.go

@@ -18,9 +18,10 @@ type contextKey string
 const UserIDContextKey contextKey = "mindsift_user_id"
 
 type Claims struct {
-	UserID      string `json:"userId"`
-	Email       string `json:"email"`
-	DisplayName string `json:"displayName"`
+	UserID       string `json:"userId"`
+	Email        string `json:"email"`
+	DisplayName  string `json:"displayName"`
+	TokenVersion int    `json:"tokenVersion"`
 	jwt.RegisteredClaims
 }
 
@@ -34,14 +35,24 @@ func CheckPassword(password, hash string) bool {
 	return err == nil
 }
 
-func GenerateToken(secret, userID, email, displayName string) (string, error) {
+func GenerateToken(secret, userID, email, displayName string, tokenVersion int) (string, error) {
+	if tokenVersion <= 0 {
+		tokenVersion = 1
+	}
+	b := make([]byte, 16)
+	_, _ = rand.Read(b)
+	jti := hex.EncodeToString(b)
+
+	now := time.Now()
 	claims := &Claims{
-		UserID:      userID,
-		Email:       email,
-		DisplayName: displayName,
+		UserID:       userID,
+		Email:        email,
+		DisplayName:  displayName,
+		TokenVersion: tokenVersion,
 		RegisteredClaims: jwt.RegisteredClaims{
-			ExpiresAt: jwt.NewNumericDate(time.Now().Add(30 * 24 * time.Hour)),
-			IssuedAt:  jwt.NewNumericDate(time.Now()),
+			ID:        jti,
+			ExpiresAt: jwt.NewNumericDate(now.Add(30 * 24 * time.Hour)),
+			IssuedAt:  jwt.NewNumericDate(now),
 			Issuer:    "mindsift",
 		},
 	}