# Native lane separator style overrides

## Goal

Make native same-direction lane separators selectable and persistently editable
in Road Workbench, using the style override pattern proven for centre lines.

## Confirmed Facts

- `compileLaneMarkings()` writes one continuous `0.12m` Polygon separator
  between each adjacent lane pair, identified by `road_id`, `left_lane_index`
  and `right_lane_index`.
- Lane separators currently have fixed light marking material and are displayed
  together with turn arrows in Workbench.
- `native-road-overrides.json` already supports validated, persistent centre
  line styles by logical native segment. The new type must not alter road-edge,
  curb or sidewalk geometry.

## Initial Requirements

- Selecting a lane separator must show its lane-pair source and a Chinese
  style editor.
- The first style catalog should mirror centre lines: white/yellow and
  dashed/solid.
- The effective style must be generated into GeoJSON, visible in Workbench,
  and consumed by native Blender/Cesium.
- Default output must remain the current white dashed-style separator.

## Out Of Scope

- Road-edge lines, curbs, sidewalks, double lines, partial ranges, lane-specific
  legal restrictions and osm2streets layers.

## Key Decision

Each override applies only to the selected adjacent lane pair. This preserves
separate marking semantics on roads with three or more lanes.

## Acceptance Criteria

- [ ] Selecting a separator exposes a Chinese style editor for its adjacent
  lane pair; choosing a style stages it automatically.
- [ ] Save and regeneration preserve the per-pair style across reloads while
  unedited separators retain the default.
- [ ] GeoJSON, Workbench, Blender and Cesium show the same effective style.
- [ ] Tests cover validation, defaults, per-pair isolation, automatic staging
  and native scene consumption.