feat(tree): complete rust family runtime checklist

- add tree shell runtime artifact contracts and page/filetree/picker runtime reducers
- sink tree.subtree.move write operation through Rust and formalize command event plans
- harden file tree search projection contract and route thin-proxy boundaries
- record completed harness tasks and move design docs into process/done

wolai-frontend/src/app/api/tree/commands/route.test.ts

@@ -1,4 +1,5 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
+import { TREE_3000_ROUTE_BOUNDARY_MANIFEST } from "@/lib/tree-route-boundary";
 
 const mockIsConvexEnabled = vi.fn(() => true);
 const mockGetAuthedConvexClient = vi.fn();
@@ -203,6 +204,19 @@ describe("/api/tree/commands route", () => {
   });
 
   it("create action 走 tree.node.create，并保留本地 scaffold 副作用", async () => {
+    expect(TREE_3000_ROUTE_BOUNDARY_MANIFEST.routes).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          id: "tree.commands",
+          role: "next-thin-proxy",
+        }),
+      ]),
+    );
+    expect(TREE_3000_ROUTE_BOUNDARY_MANIFEST.rustOwnedSemantics).toContain("tree.node.create");
+    expect(TREE_3000_ROUTE_BOUNDARY_MANIFEST.browserSubstrateDuties).toContain(
+      "新页面 scaffold 文件创建",
+    );
+
     const client = {
       mutation: vi.fn(async () => ({ activeWorkspaceId: "ws_root" })),
       query: vi.fn(),