chore: move the go code into a subfolder

apps/api/internal/zerrors/unavailable.go

@@ -0,0 +1,46 @@
+package zerrors
+
+import (
+	"fmt"
+)
+
+var (
+	_ Unavailable = (*UnavailableError)(nil)
+	_ Error       = (*UnavailableError)(nil)
+)
+
+type Unavailable interface {
+	error
+	IsUnavailable()
+}
+
+type UnavailableError struct {
+	*ZitadelError
+}
+
+func ThrowUnavailable(parent error, id, message string) error {
+	return &UnavailableError{CreateZitadelError(parent, id, message)}
+}
+
+func ThrowUnavailablef(parent error, id, format string, a ...interface{}) error {
+	return ThrowUnavailable(parent, id, fmt.Sprintf(format, a...))
+}
+
+func (err *UnavailableError) IsUnavailable() {}
+
+func IsUnavailable(err error) bool {
+	_, ok := err.(Unavailable)
+	return ok
+}
+
+func (err *UnavailableError) Is(target error) bool {
+	t, ok := target.(*UnavailableError)
+	if !ok {
+		return false
+	}
+	return err.ZitadelError.Is(t.ZitadelError)
+}
+
+func (err *UnavailableError) Unwrap() error {
+	return err.ZitadelError
+}