把 Studio 主机协议改成单向端口，并让「从视频重算」走分析入口

控制器经 AcquireGate / ImageSink / ShellNotes 与信号接线，采集 tick 用 acquire_presenter 上屏；三维测试证明分析结果已喂 3D 后，重算并入 on_analysis_requested。
验证：apps/studio 下相关 pytest 与 tools/ui_check.py（634 checks）通过。

apps/studio/tests/test_display_prefs.py

@@ -123,18 +123,35 @@ class _Host:
         self.rail_updates = 0
         self.markers = 0
         self.repaints = 0
-        self._latest_fps = latest_fps
+        self._latest_fps_value = latest_fps
 
-    def _persist_prefs(self) -> None:
+    @property
+    def latest_fps(self):
+        return self._latest_fps_value
+
+    @latest_fps.setter
+    def latest_fps(self, value) -> None:
+        self._latest_fps_value = value
+
+    # compatibility for tests that still assign ``_latest_fps``
+    @property
+    def _latest_fps(self):
+        return self._latest_fps_value
+
+    @_latest_fps.setter
+    def _latest_fps(self, value) -> None:
+        self._latest_fps_value = value
+
+    def persist_prefs(self) -> None:
         self.persisted += 1
 
-    def _refresh_status_rail(self) -> None:
+    def refresh_status_rail(self) -> None:
         self.rail_updates += 1
 
-    def _drop_render_marker(self) -> None:
+    def drop_render_marker(self) -> None:
         self.markers += 1
 
-    def _repaint_live_frame(self) -> None:
+    def repaint_live_frame(self) -> None:
         self.repaints += 1