阶段 3：实时数据 —— 采样、合成、最新帧调度与适配器 - What: sampling.py 实现 SurfaceSampler（向量化四点双线性：无效 tap 不计入也不致无效、任一**正权** tap 无效即整顶点无效且值为 NaN、域/形状不符先拒；采样表只在加载时构建）与 remap_to_domain（按 unroll 映射 gather，空洞保持 NaN 且 valid=False，保留尾随轴以支持矢量场）。composer.py 实现 SceneComposer.compose（域校验 → 采样 → 位移 → **从形变后位置重算法线**；scalar 绝不成以 display_gain；approximate 位移产生 display_illustrative(info) 诊断、calibrated 不产生、无位移则着色并报 field_unavailable）与 build_rest_frame（参考帧：scalar 全 NaN、valid 全假、descriptor=unavailable/display_only），gl_backend.rest_surface 改为委托它，避免两处定义。coordinator.py 实现完整调度：容量 1 双 mailbox、generation/来源/会话三重过期拒绝并计数、**最多一次合成在飞行**、可见性挂起/恢复、设置变更（倍率变化重合成**屏幕上那一帧**）、close 幂等；submit 只做身份与形状的廉价校验，绝不等显示。adapters.py 实现 Finger/Box 适配器：|flow| 或 depth 响应、可选经 unroll 映射 remap、设备 valid_mask 优先、域不符时**发布空**并报出所见的两个形状；一律不造位移（未标定的毫米不如没有），并新增 display_illustrative 到诊断码表（info）。assets.py 从"桩类堆"改成门面：re-export 真正实现 + SceneCompiler.compile（外壳 GLB 与预算检查；加密请求明确拒绝并指向阶段 5）。测试：shared/tests/test_scene3d_live.py 25 项（采样/无效语义/倍率只影响位置/示意形变标注/法线重算/remap 空洞/参考帧/只读数组）、apps/studio/tests/test_scene3d_coordinator.py 13 项（状态机、过期、替换计数、单飞行、submit p99<1ms、切换场景丢弃在飞结果、隐藏挂起、倍率重合成、close 幂等）、test_scene3d_adapters.py 13 项；并把三处"桩仍未实现"的过时断言改成对已实现行为的断言。docs/architecture/studio-3d-stages.md 阶段 3 记为完成。 - Why: 阶段 3 决定"屏幕上的颜色和力值到底对应什么"。三条最容易错且肉眼看不出来的规则必须由代码而不是约定来保证：无效点不是 0（NaN 与 valid 分离，否则缺口会被画成一个测量值）、显示倍率只动位置不动测量（否则色标悄悄变了含义）、以及显示永远不能给采集施加背压（容量 1 mailbox + 单飞行合成 + 廉价 submit）。 - Verification: shared 全量通过（scene3d 相关 103 项：contracts 26、assets 33、package 19、live 25）；studio 全量通过（scene3d 相关 54 项：stage1 24、skeleton 4、coordinator 13、adapters 13；GL 冒烟 10 项在真实 context 下另行通过）；ui_check 554 项 0 失败。过程中修掉 3 个真实缺陷：倍率变化时用 incoming.peek() 取不到"屏幕上那一帧"（已被消费）导致改了倍率画面不动——改为保留 _last_field_frame；display_illustrative 不在码表里被默认成 error；assets.py 里与 package/legacy 同名的重复桩类（会误导集成者，已改为门面）。另修正两处我自己的错误断言（对称凸起顶点法线本就竖直；pytest.approx 不能直接 .all()）。 - Not in this change: 手势与面板（阶段 4）；示意位移的真实来源（需要 SDK lift + 已确认尺度，现阶段 adapter 一��� displacement=None）；app_window 接线与记录隔离（阶段 4）。

apps/studio/tests/test_scene3d_skeleton.py

@@ -88,21 +88,20 @@ def test_the_widget_holds_cpu_state_and_touches_no_context(qt_app):
         widget.deleteLater()
 
 
-def test_the_stubs_name_the_stage_that_fills_them_in(qt_app):
+def test_the_remaining_stub_says_which_stage_fills_it_in(qt_app):
     """What is implemented is exercised elsewhere; what is not says so.
 
-    Stage 1 landed the camera, the dispatcher and the renderer (see
-    ``test_scene3d_stage1.py`` and ``test_scene3d_gl_smoke.py``). The remaining
-    placeholders must still fail loudly with the stage that owns them rather than
-    quietly doing nothing.
+    Stages 1 to 3 landed the camera, the dispatcher, the renderer, the sampler, the
+    composer, the schedule and the adapters. ``ThreeDPanel`` is the one piece left,
+    and it must still fail loudly with the stage that owns it rather than quietly
+    doing nothing.
     """
     from orisys_app_shared.scene3d.contracts import (
         CameraPreset,
         DisplaySettings,
-        ExpectedGeometry,
         FrameIdentity,
+        RenderStats,
     )
-    from orisys_studio.scene3d.adapters import BoxFrameAdapter, FingerFrameAdapter
     from orisys_studio.scene3d.camera import OrbitCamera
     from orisys_studio.scene3d.coordinator import ThreeDCoordinator
     from orisys_studio.scene3d.gl_backend import GLRenderer
@@ -115,34 +114,26 @@ def test_the_stubs_name_the_stage_that_fills_them_in(qt_app):
     coordinator = ThreeDCoordinator(widget, composer=object(), executor=None, max_fps=30)  # type: ignore[arg-type]
     panel = ThreeDPanel(coordinator, widget)
     try:
-        assert coordinator.state == "disabled"
-        assert coordinator.generation == 0
-        assert coordinator.superseded_frames == 0  # the mailbox is real, not a stub
-
         # Stage 1 is real: the camera works with no context at all.
         camera.set_preset(
             CameraPreset("default", (0.0, 0.0, 1.0), (0.0, 0.0, 0.0), (0.0, 1.0, 0.0), 0.7)
         )
         assert camera.matrices((100, 100)).view.shape == (4, 4)
 
+        # Stage 3 is real too: the coordinator's schedule exists with no Qt event.
+        assert coordinator.state == "disabled"
+        assert coordinator.generation == 0
+        assert coordinator.superseded_frames == 0
+        coordinator.close()  # idempotent, and safe before any scene is active
+
         for call, stage in (
-            (lambda: coordinator.activate(None, "live-A"), "stage 3"),
-            (lambda: coordinator.set_settings(DisplaySettings()), "stage 3"),
-            (lambda: coordinator.set_visible(True), "stage 3"),
-            (lambda: coordinator.close(), "stage 3"),
             (lambda: panel.set_state("ready"), "stage 4"),
-            (lambda: BoxFrameAdapter().snapshot(None, FrameIdentity("a", 1, 0, 0.0, 1), None),
-             "stage 3"),
-            (
-                lambda: FingerFrameAdapter().snapshot(
-                    None, None, FrameIdentity("a", 1, 0, 0.0, 1)
-                ),
-                "stage 3",
-            ),
+            (lambda: panel.set_render_stats(RenderStats()), "stage 4"),
+            (lambda: panel.set_diagnostic(None), "stage 4"),
         ):
             with pytest.raises(NotImplementedError) as excinfo:
                 call()
             assert stage in str(excinfo.value), (stage, str(excinfo.value))
-        del ExpectedGeometry
+        del DisplaySettings, FrameIdentity
     finally:
         widget.deleteLater()