Document VAND GPS search graph

docs/red4ext-logging-shim.md

@@ -303,6 +303,14 @@ Latest full-route join:
   route-record low-byte classes are `{0,1,2,3,4,5,7,8,9}`, and route-record
   classes 7/8/9 are highway-heavy. These are different domains, which explains
   why provider point-class tuning did not map cleanly to highway preference.
+- Later static analysis tied the search-side segment/point records to `VAND`
+  blobs in compiled navigation streamingsector resources, not directly to
+  `all.traffic_persistent`. The traffic lane hash join happens downstream in
+  the result/materialization path.
+- `tools/analyze_vand_navigation.py` decodes those `VAND` blobs from extracted
+  streamingsector JSON. In the three extracted samples, all masks were `0x0003`
+  and the dominant point classes were `1`, `4`, `5`, and `3`, matching the live
+  edge-cost trace.
 
 Current static producer lead: