feat(webui): implement workflow traffic-control view (Closes #640)

webui/app.py

@@ -42,6 +42,8 @@ from webui.lease_loader import load_lease_snapshot, snapshot_to_dict as lease_sn
 from webui.lease_views import render_leases_page
 from webui.queue_loader import load_queue_snapshot, snapshot_to_dict as queue_snapshot_to_dict
 from webui.queue_views import render_queue_page
+from webui.traffic_loader import load_traffic_snapshot, snapshot_to_dict as traffic_snapshot_to_dict
+from webui.traffic_views import render_traffic_page
 from webui.worktree_scanner import load_hygiene_snapshot, snapshot_to_dict as worktree_snapshot_to_dict
 from webui.worktree_views import render_worktrees_page
 from webui.runtime_health import load_runtime_snapshot, snapshot_to_dict as runtime_snapshot_to_dict
@@ -200,6 +202,15 @@ async def api_queue(_request: Request) -> JSONResponse:
     return JSONResponse(queue_snapshot_to_dict(load_queue_snapshot()))
 
 
+async def traffic(_request: Request) -> HTMLResponse:
+    snapshot = load_traffic_snapshot()
+    return HTMLResponse(render_traffic_page(snapshot))
+
+
+async def api_traffic(_request: Request) -> JSONResponse:
+    return JSONResponse(traffic_snapshot_to_dict(load_traffic_snapshot()))
+
+
 def _load_project_registry() -> tuple[ProjectRegistry | None, RegistryError | None]:
     """Load the registry, converting validation failure into a fail-closed pair."""
     try:
@@ -736,6 +747,8 @@ def create_app(*, bind_host: str | None = None) -> Starlette:
             Route("/system-health", system_health, methods=["GET"]),
             Route("/queue", queue, methods=["GET"]),
             Route("/api/queue", api_queue, methods=["GET"]),
+            Route("/traffic", traffic, methods=["GET"]),
+            Route("/api/traffic", api_traffic, methods=["GET"]),
             Route("/projects", projects, methods=["GET"]),
             Route("/projects/{project_id}", project_detail, methods=["GET"]),
             Route("/api/projects", api_projects, methods=["GET"]),