feat: add native road control markings

.trellis/tasks/08-13-native-road-compiler/task.json

@@ -19,7 +19,8 @@
   "pr_url": null,
   "subtasks": [],
   "children": [
-    "08-14-native-road-lane-markings"
+    "08-14-native-road-lane-markings",
+    "08-17-native-road-control-markings"
   ],
   "parent": null,
   "relatedFiles": [],

.trellis/tasks/08-17-native-road-control-markings/check.jsonl

@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}

.trellis/tasks/08-17-native-road-control-markings/design.md

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+# Native Road Control Markings Design
+
+## Architecture
+
+The native compiler remains the source of truth. It extends its canonical OSM
+parse with marked crossing nodes, then derives two additive polygon layers from
+the crossing evidence, native directed lanes, and native junction plans:
+
+```text
+OSM crossing node + native directed lane centerlines + junction plans
+    |
+    +-- crosswalks.geojson: six zebra stripe polygons per safe crossing
+    |
+    +-- vehicle_stop_lines.geojson: one safe approach stop-line polygon
+```
+
+No osm2streets GeoJSON is read. Existing crossing geometry helpers may be
+extracted or adapted only when they operate on native lane data and retain
+native provenance.
+
+## Source And Placement
+
+- A source node is eligible only when `highway=crossing` and
+  `crossing:markings` is not `no`, `none`, or `unmarked`.
+- The compiler finds native roads containing the crossing's OSM node and uses
+  the nearest compatible directed lane centerline to obtain the road tangent.
+- Crosswalk stripes are perpendicular to that tangent and constrained to the
+  native road width. Existing fixed zebra dimensions are retained initially:
+  six 0.45m stripes with 0.45m gaps, 0.45m stripe width, and a highway-based
+  stripe length.
+- A stop line is generated only when the crossing can be associated with a
+  supported junction approach and a safe outside-of-junction side. Otherwise
+  the crosswalk may remain valid but the missing stop line is diagnostic.
+- Duplicate nearby crossing nodes use a stable cluster representative so one
+  physical crosswalk does not produce duplicate stripes.
+
+## Contracts
+
+`layers/crosswalks.geojson` and `layers/vehicle_stop_lines.geojson` are Polygon
+FeatureCollections. Each feature records its crossing OSM node, source OSM way,
+native directed road/lane when available, direction, placement method, and
+`native-road-crosswalk/v1` or `native-road-stop-line/v1` provenance.
+
+The Workbench API returns both layers as `state.layers.crosswalks` and
+`state.layers.vehicleStopLines`. Its browser map uses separate toggleable
+layers and selection evidence; the scene-preview toggle leaves real control
+markings visible.
+
+`catalog.NATIVE_ROAD_LAYERS` maps the sources to existing `crosswalks` and
+`vehicle_stop_lines` material layers. This native adapter must not add them to
+the osm2streets `ROAD_LAYERS` / `SCENE_LAYERS` registry.
+
+## Compatibility And Rollback
+
+The new files are additive under `native-road/layers/`. Existing osm2streets
+output and QGIS input are unchanged. Selecting `--road-provider osm2streets`
+remains rollback. A native Blender build treats a missing new layer as an error
+rather than silently omitting a visible marking.
+
+## Risks
+
+- Crossing nodes can be detached from a routable road or lie on an ambiguous
+  multi-road segment. These become diagnostics rather than guessed geometry.
+- A physical crossing split into several OSM nodes must deduplicate stably.
+- A crosswalk near a non-supported junction may get stripes but no valid stop
+  line; this difference must be exposed in workbench provenance.

.trellis/tasks/08-17-native-road-control-markings/implement.jsonl

@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}

.trellis/tasks/08-17-native-road-control-markings/implement.md

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+# Implementation Plan
+
+1. Extend the native OSM parse/model with marked crossing-node evidence while
+   preserving existing road IDs and parser behavior.
+2. Add native crossing clustering, tangent resolution from directed lane
+   centerlines, stripe geometry, safe stop-line placement, and source
+   diagnostics.
+3. Persist the two new layers in `compile-native-roads.js`, comparison counts,
+   native build records, required native layer checks, and existing Blender
+   material mappings.
+4. Add Workbench API/state fields, Chinese layer toggles, selection evidence,
+   and summary counts while retaining scene-preview behavior.
+5. Add focused fixtures for marked and unmarked crossings, duplicate cluster
+   handling, a missing native-lane diagnostic, and output layer contracts.
+6. Run native/unit/workbench/build-stage tests, compile/check Nantaizi, then
+   build `blender,cesium,preview --road-provider native` without `package/`.
+
+## Validation
+
+```bash
+npm run test:native-road
+npm run test:road-workbench
+npm run test:build-stages
+npm run road:compile -- --config config/areas/nantaizi-lake-innovation-valley.json
+npm run road:check -- --config config/areas/nantaizi-lake-innovation-valley.json
+npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json \
+  --stages blender,cesium,preview --road-provider native
+```
+
+Rollback is selecting `--road-provider osm2streets`; no legacy output path is
+changed.

.trellis/tasks/08-17-native-road-control-markings/prd.md

@@ -0,0 +1,61 @@
+# Native road control markings
+
+## Goal
+
+Give Nantaizi's native-road provider inspectable, source-traceable crosswalk
+and vehicle stop-line geometry, so intersection control markings do not depend
+on the osm2streets render output.
+
+## Confirmed Facts
+
+- Native road output already owns road surfaces, sidewalks, lane separators,
+  repeated direction arrows, and explicit junction-turn arrows.
+- Nantaizi's OSM input contains explicit marked crossings, including zebra and
+  traffic-signal crossings. The existing osm2streets output currently has 48
+  crosswalk-stripe polygons and 8 stop-line polygons.
+- `build-osm2streets-qgis.js:1067` derives these markings from crossing nodes
+  plus osm2streets driving lanes. Native must not read that rendered geometry;
+  it can reuse only the tested geometry rules after adapting them to native
+  directed lanes and junction plans.
+- Existing Blender materials already provide `crosswalks` and
+  `vehicle_stop_lines`; native may map into them without changing the legacy
+  osm2streets layer registry.
+
+## Requirements
+
+- R1: Native compilation uses explicit marked OSM crossing nodes only, and
+  emits crosswalk-stripe polygons plus approach stop lines only where safe
+  native directed-road placement exists.
+- R2: Each generated feature preserves crossing node, OSM road, native road or
+  lane, direction, placement method, and relevant junction provenance.
+- R3: The Road Workbench independently toggles, selects, and describes native
+  crosswalks and stop lines in Chinese.
+- R4: Native Blender and Cesium builds consume both layers with the existing
+  control-marking materials; no `package/` publication is part of validation.
+- R5: Missing compatible road context, ambiguous geometry, and unsupported
+  crossing inputs are diagnostics; the compiler must not invent a crossing.
+
+## Acceptance Criteria
+
+- [ ] Nantaizi native output contains valid `crosswalks.geojson` and
+  `vehicle_stop_lines.geojson` features with source-traceable properties,
+  without reading osm2streets rendered layers.
+- [ ] A Workbench user can toggle and select either marking type and see the
+  crossing node, associated road/direction, and placement evidence.
+- [ ] Native Blender/Cesium output contains both marking types using existing
+  materials, after `blender,cesium,preview --road-provider native` and without
+  publishing `package/`.
+- [ ] Tests cover a marked crossing, an unmarked crossing skip, a missing or
+  ambiguous native-road placement skip, and output-layer contract checks.
+
+## Out Of Scope
+
+- Hand-placed control-marking overrides, traffic-signal state-machine changes,
+  freehand polygon editing, processing another region, and importing
+  osm2streets-rendered crosswalk geometry.
+
+## Key Decision
+
+The first version is explicit-OSM-only. This is feasible for Nantaizi and
+keeps control markings evidence-backed; missing data remains a diagnostic for
+OSM improvement rather than a silent geometric guess.

.trellis/tasks/08-17-native-road-control-markings/task.json

@@ -0,0 +1,26 @@
+{
+  "id": "native-road-control-markings",
+  "name": "native-road-control-markings",
+  "title": "Native road control markings",
+  "description": "",
+  "status": "in_progress",
+  "dev_type": null,
+  "scope": null,
+  "package": null,
+  "priority": "P2",
+  "creator": "dingkang",
+  "assignee": "dingkang",
+  "createdAt": "2026-08-17",
+  "completedAt": null,
+  "branch": null,
+  "base_branch": "feature/native-road-compiler",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": "08-13-native-road-compiler",
+  "relatedFiles": [],
+  "notes": "",
+  "meta": {}
+}