feat(lidar): add point-aligned ground review

docs/10_EXTERNAL_PERCEPTION_WORKER.md

@@ -24,6 +24,21 @@ read-only `/api/v1/lidar/ground-benchmarks` surface therefore publishes
 `production_promotion=false` until an independent annotation generation or an
 admitted raw scan closes the input gate.
 
+The companion read-only
+`/api/v1/lidar/ground-benchmarks/{benchmark_id}/frames/{frame_index}` endpoint
+returns one bounded, path-free point-aligned frame. The Control Station renders
+that evidence in Three.js with unrestricted orbit, pan and zoom plus
+intensity/current/candidate/disagreement color modes. The browser never runs
+Patchwork++, parses private firmware or receives a filesystem path.
+
+Static K1 3.0.2 firmware evidence confirms that the appliance internally uses
+a Livox MID-360 point/IMU path with richer timestamp/ring semantics and a
+configured MQTT point-cloud downsample factor of four. This creates a concrete
+next integration target—an admitted onboard export or bag contract—but does
+not change the authority or input acceptance of existing `lio_pcl` recordings.
+The 1.27 m operator-height profile is likewise explicit and reproducible, but
+remains `operator-estimated` rather than runtime-calibrated.
+
 ## Boundary
 
 ```text