Present replay 3D with the cursor and open Analyze on a remembered video

Replay left the 3D pane on the rest mesh or a sparse overlay, and Analyze skipped the setup dialog unless the file was re-picked. Live Run no longer starts a chain on a video path. Verified with Studio tests for flush, overlay mask, Analyze open, live-video refusal, and locales.

apps/studio/tests/test_scene3d_view.py

@@ -208,6 +208,36 @@ def test_a_platform_without_a_context_says_so_instead_of_showing_an_empty_view(
 
 
 # --------------------------------------------------------- one state, two controls
+def test_an_analysis_packet_ticks_the_3d_pane(make_window, monkeypatch):
+    """Replay has no run timer: submit must flush the compose so the frame is presented."""
+    window = make_window(sensor_type="finger")
+    try:
+        flushes: list[int] = []
+        submitted: list[object] = []
+        policies: list[object] = []
+
+        class _View:
+            def set_overlay_policy(self, policy) -> None:
+                policies.append(policy)
+
+            def submit_packet(self, packet) -> None:
+                submitted.append(packet)
+
+            def flush(self) -> None:
+                flushes.append(1)
+
+        # A full Scene3DView needs GL; only the submit/flush seam is under test here.
+        window.mesh3d_panel._view = _View()  # noqa: SLF001
+        monkeypatch.setattr(window, "_connect_analysis_display", lambda panel: True)
+        window.show_analysis_packet(object())
+        assert submitted, "the analysis packet never reached the 3D producer"
+        assert policies, "the overlay policy was not handed to the 3D view"
+        assert flushes, "the pane was not flushed after submit"
+    finally:
+        window.mesh3d_panel._view = None  # noqa: SLF001
+        window.close()
+
+
 def test_the_pane_and_the_view_menu_are_the_same_flag(make_window):
     window = make_window(sensor_type="finger")
     try: