fix: animation-only FBX assets loadable; clip data viewer

Pure-animation FBX (no meshes, skeleton clips only) was rejected at
the cache layer: ParsedModel::Valid() required non-empty meshes, so
Model::FromParsed/LoadModel returned null and the asset never made it
into the cache. Animation assets are now first-class:

- ParsedModel::Valid() = meshes or clips non-empty; parse failures
  (both empty) still rejected. Empty-mesh consumers already guarded
  (rendering skips empty mesh loop, mesh collider falls back to Box)
- ParseFromDisk: fix null-deref when assimp returns a null scene
- AssetCache::Find(path) + AssetManager::GetModelByPath for panels
- Asset Browser hover card shows meshes/bones/clips for loaded models
- Inspector model line flags "animation-only" when meshes == 0
- Animation section: collapsible clip data table (name/duration/
  channel count) to verify bone-name matching of attached clips

App/editor/InspectorPanel.cpp

@@ -329,9 +329,23 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
                     model != nullptr)
                 {
                     const auto& clips = model->GetClips();
-                    ImGui::Text("model: valid (%u clips, %u bones)",
-                                static_cast<unsigned>(clips.size()),
-                                static_cast<unsigned>(model->GetBoneCount()));
+                    if (model->GetMeshes().empty())
+                    {
+                        // 纯动画容器（无网格）：不能作为渲染模型，提示
+                        // 挂到 MeshRenderer 没有视觉效果
+                        ImGui::TextColored(ImVec4(1.0f, 0.75f, 0.2f, 1.0f),
+                                           "model: animation-only "
+                                           "(%u clips, %u bones, no meshes)",
+                                           static_cast<unsigned>(clips.size()),
+                                           model->GetBoneCount());
+                    }
+                    else
+                    {
+                        ImGui::Text("model: valid (%u meshes, %u clips, %u bones)",
+                                    static_cast<unsigned>(model->GetMeshes().size()),
+                                    static_cast<unsigned>(clips.size()),
+                                    model->GetBoneCount());
+                    }
                 }
                 else
                 {
@@ -910,6 +924,45 @@ void InspectorPanel::Draw(const EditorContext& ctx, entt::entity selected)
                     ImGui::Text("t: %.2f / %.2f s", anim->time,
                                 clips[anim->clipIndex].duration);
                 }
+                // 动画数据表：每个 clip 的时长与有效轨道数（attach 进来的
+                // 外部动画在此核对骨骼匹配结果——轨道数明显偏少 = 骨骼
+                // 命名不同源被跳过）
+                if (ImGui::TreeNode("clip data"))
+                {
+                    ImGui::Columns(3, nullptr, false);
+                    ImGui::SetColumnWidth(0, 150.0f);
+                    ImGui::SetColumnWidth(1, 90.0f);
+                    ImGui::TextUnformatted("name");
+                    ImGui::NextColumn();
+                    ImGui::TextUnformatted("dur (s)");
+                    ImGui::NextColumn();
+                    ImGui::TextUnformatted("channels");
+                    ImGui::NextColumn();
+                    ImGui::Separator();
+                    for (const auto& c : clips)
+                    {
+                        const bool curClip =
+                            &c == &clips[static_cast<size_t>(
+                                       std::clamp(anim->clipIndex, 0,
+                                                  static_cast<int>(clips.size()) - 1))];
+                        if (curClip)
+                        {
+                            ImGui::TextColored(ImVec4(0.3f, 0.85f, 0.4f, 1.0f),
+                                               ">%s", c.name.c_str());
+                        }
+                        else
+                        {
+                            ImGui::TextUnformatted(c.name.c_str());
+                        }
+                        ImGui::NextColumn();
+                        ImGui::Text("%.2f", c.duration);
+                        ImGui::NextColumn();
+                        ImGui::Text("%u", static_cast<unsigned>(c.channels.size()));
+                        ImGui::NextColumn();
+                    }
+                    ImGui::Columns(1);
+                    ImGui::TreePop();
+                }
             }
             else
             {