chore(task): plan native-only pipeline replacement

.trellis/tasks/08-18-native-only-pipeline-replacement/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/08-18-native-only-pipeline-replacement/design.md

@@ -0,0 +1,51 @@
+# Design
+
+## Provider Boundary
+
+`build-area.js` will resolve a native provider by default. Native stages consume only OSM, native
+road overrides, and `native-road/` outputs. Legacy `intermediates`, `reimport`, and osm2streets
+Blender input remain behind explicit legacy selection and keep their existing output contract.
+
+## Native Data Flow
+
+```text
+OSM + native-road-overrides.json
+  -> compile-native-roads.js
+  -> native-road/layers/*.geojson + compiled.json + traffic-signals.json
+  -> Blender generate_scene.py --native-road --traffic-signals
+  -> .blend
+  -> Cesium/package GLB + manifest + runtime/traffic-signals.json
+  -> preview HTML + optional native vehicle route
+```
+
+The native compiler is the sole authority for road geometry, lane semantics, intersection surfaces,
+stop lines, and signal runtime. No native stage reads `geojsonDir` or legacy assembly files.
+
+## Preview Route
+
+Add a native route adapter that derives route segments from `compiled.json` model roads/endpoints and
+native lane/connector geometry. If the native route cannot be built for a valid area, preview remains
+usable without vehicles and records a warning; missing legacy osm2streets lane polygons is never a
+hard failure on the native path.
+
+## Package Runtime
+
+The package stage will copy the native-road signal runtime into its staging runtime directory and
+declare it in the package manifest. Preview receives the package-relative runtime URI. Legacy signal
+runtime publication remains conditional on the legacy provider.
+
+## Configuration And Compatibility
+
+`roadProvider` defaults to `native`; native stages are the default stage set. QGIS config fields and
+legacy stage aliases remain accepted for explicit migration/debug commands, but native manifests and
+docs do not claim them as inputs.
+
+The Workbench may continue to read an existing `geojsonDir` only for an explicitly labeled reference
+layer and comparison counters. Those reads are optional, isolated from native compile state, and must
+never become required inputs for `/api/state`, native editing, package publication, or preview.
+
+## Rollback
+
+The original QGIS/osm2streets branch baseline is tagged
+`qgis-original-baseline-20260818` on `main`. Reverting the native-only work can therefore use the tag
+or switch to `main`; no destructive cleanup of legacy scripts is required.

.trellis/tasks/08-18-native-only-pipeline-replacement/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/08-18-native-only-pipeline-replacement/implement.md

@@ -0,0 +1,27 @@
+# Implementation Plan
+
+1. Add native provider/default-stage contracts and explicit legacy provider routing.
+2. Make package publication and stage manifests consume native runtime artifacts.
+3. Replace preview's hard dependency on osm2streets lane/network/intersection files with a native
+   route adapter and optional-route behavior.
+4. Audit Blender, Cesium, preview, diagnostics, and area config for native-path legacy reads; retain
+   only the Workbench's optional, clearly labeled osm2streets reference layer.
+5. Update README/config/spec documentation and add dependency-boundary regression tests.
+6. Run native-only tests with legacy directories absent, then run focused legacy compatibility tests.
+7. Run area compile/check plus available Blender/Cesium/preview validation; record any environment-only
+   limitation without weakening native contracts.
+
+## Validation
+
+```bash
+npm run test:native-road
+npm run test:traffic-signals
+npm run test:road-workbench
+npm run test:preview-assets
+npm run road:compile -- --config config/areas/nantaizi-lake-innovation-valley.json
+npm run road:check -- --config config/areas/nantaizi-lake-innovation-valley.json
+node --check scripts/build-area.js
+```
+
+The final gate must also exercise a native-only config/output directory without QGIS/osm2streets
+intermediates and assert package/runtime/preview outputs.

.trellis/tasks/08-18-native-only-pipeline-replacement/prd.md

@@ -0,0 +1,63 @@
+# Complete native-only pipeline replacement
+
+## Goal
+
+Make the native road compiler the primary and complete production path. A normal build of an
+area must generate Blender, Cesium/package, and preview outputs directly from OSM plus native
+artifacts without installing or running QGIS, GDAL, or osm2streets.
+
+The existing QGIS/osm2streets workflow remains available only as an explicit legacy/debug path and
+an optional Workbench reference layer. It is protected by the `qgis-original-baseline-20260818` tag
+on `main`.
+
+## Confirmed Current Gaps
+
+- `normalizeAreaConfig()` defaults `stages.intermediates` to true and `blender.roadProvider` to
+  `osm2streets`.
+- `build-area.js` sends `intermediates` to `build-osm2streets-qgis.js` and `reimport` to GDAL/QGIS.
+- Native Blender input exists, but `preview` still requires `osm2streets_web_out/lane_polygons.geojson`,
+  `network.json`, and `intersection_surface.geojson` for vehicle-route generation.
+- Package/runtime publication still copies `outputs.<area>.trafficSignals` from the legacy GeoJSON
+  directory instead of the native-road runtime artifact.
+- README, config templates, stage names, and manifest descriptions still present QGIS as the normal
+  workflow.
+
+## Requirements
+
+- R1: Native is the default road provider and default build stages do not invoke QGIS, GDAL, or
+  osm2streets.
+- R2: Native build generates all required road, lane, marking, junction, stop-line, and traffic-signal
+  inputs consumed by Blender and preview; no native stage reads `osm2streets_web_out`.
+- R3: Native package publication copies runtime traffic signals and any other runtime descriptors
+  from native-road outputs, with stable package-relative URIs.
+- R4: Native preview route generation uses native lane/road topology and native intersection geometry,
+  or explicitly omits the optional vehicle route when native route data is unavailable; it must not
+  fail because legacy osm2streets files are absent.
+- R5: QGIS/osm2streets stages remain callable only through an explicit legacy provider/stage selection
+  and are not part of native defaults or native manifests. Workbench may display their existing
+  GeoJSON as a clearly labeled reference/comparison layer, but native editing, compile, package, and
+  preview results must not depend on it.
+- R6: Documentation and config templates describe native-only as the primary workflow and clearly
+  mark the legacy path as transitional/debug-only.
+
+## Acceptance Criteria
+
+- [ ] A clean native-only area build succeeds with QGIS absent and no `osm2streets-js-node` runtime
+  call, producing `.blend`, package manifest/GLB, runtime traffic signals, and preview HTML.
+- [ ] Native preview opens when `osm2streets_web_out/` is absent; optional vehicle cruise either uses
+  native route data or is omitted with a visible non-fatal diagnostic.
+- [ ] Native package manifest contains runtime traffic-signal anchors sourced from
+  `native-road/traffic-signals.json`; disabled signals remain absent from runtime.
+- [ ] Workbench edits survive save, native recompile, package publication, and preview reload without
+  QGIS or osm2streets files.
+- [ ] Explicit legacy QGIS/osm2streets commands still pass their existing focused tests, but no longer
+  run when using native defaults.
+- [ ] Workbench remains usable when the optional osm2streets reference directory is absent; only the
+  reference layer/comparison counters degrade to unavailable.
+- [ ] Tests assert the native-only dependency boundary and the QGIS baseline tag is documented.
+
+## Out Of Scope
+
+- Reimplementing QGIS editing features in the native compiler beyond existing Workbench controls.
+- Deleting legacy scripts or historical output files in this task; they remain rollback/debug tooling.
+- Changing Blender/Cesium visual semantics unrelated to removing the input dependency.

.trellis/tasks/08-18-native-only-pipeline-replacement/task.json

@@ -0,0 +1,26 @@
+{
+  "id": "native-only-pipeline-replacement",
+  "name": "native-only-pipeline-replacement",
+  "title": "Complete native-only pipeline replacement",
+  "description": "",
+  "status": "planning",
+  "dev_type": null,
+  "scope": null,
+  "package": null,
+  "priority": "P2",
+  "creator": "dingkang",
+  "assignee": "dingkang",
+  "createdAt": "2026-08-18",
+  "completedAt": null,
+  "branch": null,
+  "base_branch": "feature/native-road-compiler",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": null,
+  "relatedFiles": [],
+  "notes": "",
+  "meta": {}
+}