Add live spatial weight tuning

docs/compaction-handoff.md

@@ -71,6 +71,15 @@ Current date/time context: 2026-06-26, local timezone America/Chicago.
   `toolbox run -c 2077 tools/build_red4ext_shim.sh`.
 - The resulting DLL remains uninstalled. Game install still has only
   `EdgeWeightGPS.dll.disabled`, not an active plugin DLL.
+- Follow-up live-tuning support adds
+  `red4ext/plugins/EdgeWeightGPS/spatial_weights.bin`: five little-endian
+  float32 values in highway, road, GPSOnly, pavement, unknown order. The plugin
+  polls this file on route-producer entry, so changing it and replotting a route
+  applies new weights without rebuild/relaunch.
+- `tools/write_spatial_weights.py` can write the active file or generate
+  presets. Generated presets live in `work/spatial-weights/`:
+  `vanilla.bin`, `current.bin`, `highway-free.bin`,
+  `highway-expensive.bin`, and `surface-extreme.bin`.
 
 Important caveat:
 

docs/red4ext-logging-shim.md

@@ -81,6 +81,15 @@ Active build note:
   `GPSEdgeCost` (`0x44f838`), samples a generated traffic-lane spatial grid
   using the search-state coordinates, and applies highway/road/pavement
   multipliers to returned edge costs.
+- When the spatial patch is enabled, the plugin hot-reloads
+  `spatial_weights.bin` from the same directory as the DLL. The file is exactly
+  five little-endian float32 values in this order:
+  `highway`, `road`, `GPSOnly`, `pavement`, `unknown`.
+- `tools/write_spatial_weights.py` writes that file directly, or can generate
+  named preset files under `work/spatial-weights/` for live copy-over testing.
+  The prepared presets are:
+  `vanilla`, `current`, `highway-free`, `highway-expensive`, and
+  `surface-extreme`.
 - The old verbose local-search probe is still available behind
   `kEnableGpsLocalSearchHooks`. It hooks `GPSSearch` (`0x44f054`),
   `GPSResolveHandle` (`0x44e1a8`), `GPSEdgeCost` (`0x44f838`), and the two