优化本机重置不可用提示

当系统通知或本机重置通道不可用时，向运维人员显示明确的中文原因，并补充回归测试。

backend/internal/adminconsole/flow.go

@@ -90,6 +90,10 @@ func runConnected(ctx context.Context, conn net.Conn, screen terminal) error {
 		}
 	}
 	if err := resetFlow(ctx, client, screen); err != nil {
+		if errors.Is(err, localreset.ErrUnavailable) {
+			showResetFailure(screen, err)
+			return localreset.ErrProtocol
+		}
 		_ = screen.Show("密码重置未完成：操作已取消、验证失败、会话过期或保存失败。请检查服务日志后重新启动。")
 		return localreset.ErrProtocol
 	}
@@ -99,6 +103,14 @@ func runConnected(ctx context.Context, conn net.Conn, screen terminal) error {
 	return nil
 }
 
+func showResetFailure(screen terminal, err error) {
+	message := `密码重置未完成：操作已取消、验证失败、会话过期或保存失败。请检查服务日志后重新启动。`
+	if errors.Is(err, localreset.ErrUnavailable) {
+		message = `密码重置未完成：验证码发送服务或本机重置通道不可用。请先恢复系统通知服务后重新启动。`
+	}
+	_ = screen.Show(message)
+}
+
 func resetFlow(ctx context.Context, client resetClient, screen terminal) error {
 	methods := client.Methods()
 	if len(methods) != 1 || methods[0].ID != "email" {

backend/internal/adminconsole/flow_test.go

@@ -14,6 +14,7 @@ type testTerminalInput struct {
 	values   []string
 	hidden   []bool
 	prompts  []string
+	shown    []string
 	failAt   int
 	readHook func(int)
 }
@@ -36,7 +37,10 @@ func (s *testTerminalInput) Read(ctx context.Context, prompt string, hidden bool
 	}
 	return s.values[index-1], nil
 }
-func (*testTerminalInput) Show(string) error { return nil }
+func (s *testTerminalInput) Show(message string) error {
+	s.shown = append(s.shown, message)
+	return nil
+}
 
 type testResetClient struct {
 	methods  []localreset.Method
@@ -133,6 +137,14 @@ func TestAdminConsoleFailureNeverSubmitsPassword(t *testing.T) {
 	}
 }
 
+func TestAdminConsoleShowsUnavailableResetCause(t *testing.T) {
+	screen := &testTerminalInput{}
+	showResetFailure(screen, localreset.ErrUnavailable)
+	if len(screen.shown) != 1 || !strings.Contains(screen.shown[0], `验证码发送服务或本机重置通道不可用`) {
+		t.Fatalf(`未显示SMTP或本机通道不可用提示：%v`, screen.shown)
+	}
+}
+
 func TestAdminConsoleRejectsAllArgumentBasedInput(t *testing.T) {
 	for _, args := range [][]string{
 		{"--password", "TestPass123!"}, {"--config", "scert.json"}, {"--code-output", "reset-code"}, {"TestPass123!"}, {"--help"},