fix(api): relax account password validation

backend/api/internal/logic/common/base.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"reflect"
 	"strings"
+	"unicode/utf8"
 
 	"git.apinb.com/bsm-sdk/core/errcode"
 	"git.apinb.com/bsm-sdk/core/infra"
@@ -16,6 +17,14 @@ import (
 	"gorm.io/gorm"
 )
 
+// AccountPasswordMinLength 是账号密码允许的最低字符数。
+const AccountPasswordMinLength = 6
+
+// IsValidAccountPassword 仅校验账号密码的最低字符长度。
+func IsValidAccountPassword(password string) bool {
+	return utf8.RuneCountInString(password) >= AccountPasswordMinLength
+}
+
 // PasswordHash creates the shared password representation used by account modules.
 func PasswordHash(password string) (string, error) {
 	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)

backend/api/internal/logic/common/password_test.go

@@ -0,0 +1,24 @@
+package common
+
+import "testing"
+
+func TestIsValidAccountPassword(t *testing.T) {
+	tests := []struct {
+		name     string
+		password string
+		want     bool
+	}{
+		{name: "five characters", password: "12345", want: false},
+		{name: "six digits", password: "123456", want: true},
+		{name: "six letters without complexity", password: "abcdef", want: true},
+		{name: "six unicode characters", password: "密码密码密码", want: true},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if got := IsValidAccountPassword(test.password); got != test.want {
+				t.Fatalf("IsValidAccountPassword(%q) = %v, want %v", test.password, got, test.want)
+			}
+		})
+	}
+}