fix(lab): preserve replay view and restore SLAM semantics

experiments/perception/M49_TGS_FULL_SHADOW_ACCEPTANCE_2026-08-26.md

@@ -20,13 +20,14 @@ correct for vegetation, terrain, gaps or the future vehicle envelope.
 
 | Item | Identity |
 | --- | --- |
-| LAB result | `m49-tgs-full-shadow-0faeaaf3aba8dccae974eab51ff9cccf264a13ec285abb1920c1e5a09a7e87bc` |
+| LAB result | `m49-tgs-full-shadow-ef98de7db7596d48e8c8c0549ce68e6704ee03e87c8c4bcf1e3e748b7ccb032e` |
 | Worker run | `Worker 006 / ravnoves00-full-001` |
 | Mission Core revision used by Worker | `40c850b167dda366d8aa45d828520168affaf9fd` |
 | Deterministic Worker artifact | `5e0ea16c7a5cc760463836718b0cd8b0006ffc4b202e5f706a20a86ef2f912ab` |
 | Source pack SHA-256 | `0685d24219d8236caf8b7f1685e93f6d6b59e7fd015a768d88a92bbe8b154944` |
 | TGS config SHA-256 | `c2e07010aaee78259d36c057962d6bfb885349251ff7356d867e5813e632881c` |
 | Linked visual result | `m4-threat-replay-2a953c5f27f2a5b1dddc5c658c1de2c323d7796084a099c024987a1da03aa324` |
+| Linked semantic result | `e47-semantic-slam-f8c53ba12e9719856195890c7dcd2ba6c114434674159f948064368012e6b3bc` |
 
 The profile is a `0.45 m`, `12 m` radius, `1 s` causal rolling
 `map-gravity-local` costmap. The four states remain separate:
@@ -62,7 +63,9 @@ source points. This preserves chronology without inventing free space.
 
 The immutable result is published on the canonical Mission Core service at
 port `8000`. The LAB reuses the recorded camera timeline and exposes independent
-`SOURCE POINTS`, `TGS COSTMAP`, `3D` and `PLAN` controls.
+`SOURCE POINTS`, `LOCAL SLAM`, `TGS COSTMAP`, `SEMANTICS`, `3D` and `PLAN`
+controls. The semantic mask is the exact E47 full-route archive bound to the
+same M4 camera result; it remains diagnostic and does not change TGS states.
 
 The first implementation fetched one large JSON frame at a time. Browser QA
 showed that this was only intermittently exact at `1×`. The published viewer
@@ -73,6 +76,14 @@ showed the loading placeholder. A real missing-LiDAR frame was separately
 accepted with `0 source points`, `2,244 unobserved`, `0 occupied` and no retained
 previous cloud.
 
+A follow-up playback acceptance fixed a UI lifecycle defect that remounted the
+Three.js scene while the next TGS frame crossed the React buffer boundary. The
+scene now retains the last sealed classified frame until the exact next frame
+arrives, so orbit controls and the operator-selected view survive continuous
+playback. Twelve consecutive `250 ms` playback samples kept one mounted 3D
+canvas, a visible bounded `LOCAL SLAM` surface and the synchronized E47 video
+mask. Pausing is no longer required to rotate, pan or zoom the 3D view.
+
 ## Sealed evidence
 
 | File | Bytes | SHA-256 |