feat(studio): 三维视图接入产品（阶段 4：界面、生命周期与记录隔离）

- What: `Scene3DView` 装配（widget/相机/渲染器/合成器/协调器/适配器），`asset_source`
  只查找并后台加载已编译的 `.oryscene` 包，`scene3d/prefs` 持久化并**修复**显示设置，
  `ui/mesh3d_panel` 用真实容器替换占位标签（无 GL/无包/包被拒/传感器不匹配各显示一行原因），
  `main.py` 在 `QApplication` 之前选定 GL profile，`app_window` 接线：3D 作为采集线程上的
  第二个 sink、`_on_run_tick` 驱动 `tick()`、视图切换与 `closeEvent` 释放、preferences 落盘。
- Why: 阶段 4 的验收要求"三维开关不影响采集/记录/力曲线"，并把阶段 1 留下的
  "开/关三维 CSV 一致"这条补上；同时把"没有 context"从"看起来像在工作"变成可显示的终态。
- Verification: app 侧 test_scene3d_view 28 项、test_scene3d_gl_smoke 14 项（真实 GPU）、
  adapters 17 项、skeleton 4 项、stage1 24 项、coordinator 13 项、ui_smoke 86 项；
  shared 侧 contract 26 / assets 33 / package 19 / live 25；`ui_check.py` 566 项检查 0 失败
  （新增 "3D pane" 段 12 项）；`locale_check.py` 302 个字面 key 0 缺失、中英各 377 key 对齐；
  记录隔离：同一 96 帧会话挂/不挂 3D 消费者，`forces.csv` 逐字节相同、有效样本数与记录问题数相同；
  生产者预算：合成器放慢到 50 ms 时 `submit_packet` p99 < 1 ms。
- Not in this change: 示意位移（`displacement_sensor_m`）仍未接入（需 SDK lift 与已确认尺度）；
  ARM 板卡适配（按用户要求暂缓）；包签名/AES-GCM 与长时性能报告（阶段 5）；
  仓库中仍未提供 `.oryscene` 包（发布产物，且其单位与变换必须由人声明）。

apps/studio/config/locales/en_US.json

@@ -156,8 +156,13 @@
     "plots": "Force Charts",
     "cal": "Calibration",
     "mesh3d": "3D mesh",
-    "mesh3d_empty": "Finger 3D view placeholder —\nOpen3D mesh coming later",
-    "mesh3d_empty_tip": "3D mesh preview for finger sensors"
+    "mesh3d_empty": "3D surface view",
+    "mesh3d_empty_tip": "3D surface view for finger sensors (coloured by the live deformation field)",
+    "mesh3d_no_scene": "No 3D scene for this sensor type",
+    "mesh3d_no_asset": "No compiled 3D scene installed.\nA scene package (*.oryscene) is looked for in:\n{directory}\nBuild one with tools/scene_assets/compile_scene.py — the names of the files it needs are in its --help. Only the 3D view is affected; measuring, recording and the charts work as usual.",
+    "mesh3d_loading": "Loading 3D scene {name}…",
+    "mesh3d_rejected": "The 3D scene was refused: {message}\nOnly the 3D view is affected; measuring, recording and the charts work as usual.",
+    "mesh3d_unavailable_gl_reason": "3D is not available on this machine: {reason}\nMeasuring, recording and the charts work as usual."
   },
   "chart": {
     "fn": "FN",
@@ -367,5 +372,36 @@
     "config_missing": "Sensor config not found for {type}",
     "units_raw_fallback": "Calibration unavailable — showing raw units",
     "reveal_failed": "Could not reveal config: {error}"
+  },
+  "scene3d": {
+    "enable": "Show the 3D view",
+    "preset": "View",
+    "housing": "Housing",
+    "deform": "Exaggerate",
+    "deform_tip": "Display-only magnification of the measured deformation. It changes the picture and nothing else: the recorded data, the calibration and the camera are not touched.",
+    "scale": "Colour scale",
+    "scale_range": "Range",
+    "scale_range_tip": "Bounds of the colour scale in fixed mode. In automatic mode the range comes from the valid samples of the frame on screen, so a quantity whose size differs by orders of magnitude is still readable.",
+    "scale_fixed": "Fixed",
+    "scale_auto": "Automatic",
+    "max_fps": "Display rate",
+    "max_fps_tip": "How many frames per second the 3D view draws. A display budget only: the camera and the recording are unaffected, and a dropped frame here is never a dropped sample.",
+    "reset_view": "Reset view",
+    "legend": "{quantity} [{unit}] · {quality}",
+    "legend_none": "No measurement on screen — the surface model is shown uncoloured",
+    "quality_calibrated": "calibrated",
+    "quality_approximate": "relative deformation, illustration",
+    "quality_display_only": "display only",
+    "state_disabled": "3D view is off",
+    "state_loading": "Loading the scene…",
+    "state_ready": "Ready — waiting for the first frame",
+    "state_live": "Live",
+    "state_no_data": "No valid measurement in this frame — showing the surface model",
+    "state_suspended": "Suspended (the view is hidden)",
+    "state_unavailable": "3D is unavailable",
+    "severity_info": "Note",
+    "severity_warning": "Warning",
+    "severity_error": "Error",
+    "stats": "shown {displayed} · dropped {dropped} · compose {compose} ms · paint {paint} ms"
   }
 }