feat(polygon): qualify GOOSE ground providers

src/k1link/web/app.py

@@ -44,7 +44,7 @@ from k1link.web.plugin_runtime import (
     PluginNotFoundError,
     PluginRuntimeUnavailableError,
 )
-from k1link.web.polygon_api import build_polygon_router
+from k1link.web.polygon_api import build_polygon_router, configured_polygon_runs_root
 from k1link.web.session_api import build_session_router
 
 REPOSITORY_ROOT = Path(__file__).resolve().parents[3]
@@ -398,7 +398,12 @@ app.include_router(
         point_color_renderers=plugin_environment.point_color_renderers,
     )
 )
-app.include_router(build_polygon_router())
+app.include_router(
+    build_polygon_router(
+        root_provider=lambda: configured_polygon_runs_root()
+        or REPOSITORY_ROOT / ".runtime" / "polygon-runs"
+    )
+)
 app.include_router(
     build_lidar_router(
         root_provider=lambda: (