fix(api): relax account password validation

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)
+			}
+		})
+	}
+}