feat: harden runtime import and frontend verification workflows

internal/host/sub2api/capability_probe.go

@@ -28,7 +28,7 @@ func (c *Client) ProbeCapabilities(ctx context.Context) (HostCapabilities, error
 		return HostCapabilities{}, err
 	}
 
-	accountTest, err := c.probeEndpoint(ctx, http.MethodGet, "/api/v1/admin/accounts/__probe__/test", nil)
+	accountTest, err := c.probeEndpoint(ctx, http.MethodPost, "/api/v1/admin/accounts/__probe__/test", map[string]any{})
 	if err != nil {
 		return HostCapabilities{}, err
 	}

internal/host/sub2api/sub2api_test.go

@@ -1103,6 +1103,9 @@ func TestProbeCapabilitiesWithMock(t *testing.T) {
 	callCount := 0
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		callCount++
+		if r.URL.Path == "/api/v1/admin/accounts/__probe__/test" && r.Method != http.MethodPost {
+			t.Fatalf("account test probe method = %s, want POST", r.Method)
+		}
 		w.Header().Set("Content-Type", "application/json")
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write([]byte(`{"data":[]}`))