feat: rename graph titles with select-then-edit interaction

tests/workspace.test.mjs

@@ -1,6 +1,6 @@
 import { test } from "node:test";
 import assert from "node:assert/strict";
-import { boardHref, createBoard, DEFAULT_BOARD_TITLE, loadWorkspaceHome } from "../src/lib/workspace.ts";
+import { boardHref, createBoard, renameBoard, DEFAULT_BOARD_TITLE, loadWorkspaceHome } from "../src/lib/workspace.ts";
 
 test("profile and workspace reads both start before either completes", async () => {
   const calls = [];
@@ -101,3 +101,36 @@ test("graph URLs preserve workspace identity and safely encode route segments",
   assert.equal(boardHref("space/a", "id?b"), "/dashboard/space%2Fa/id%3Fb");
   assert.equal(boardHref("demo", "board", true), "/dashboard/demo/board?demo=1");
 });
+
+
+test("renaming reads the latest version and preserves description and content", async () => {
+  const calls = [];
+  const content = { schema_version: 1, preserved: { key: "value" } };
+  const renamed = await renameBoard(async (path, options) => {
+    calls.push(path);
+    if (!options) return { id: "board", workspace_id: "space", kind: "board", title: "Old", version: 7, description: "Keep this", content };
+    assert.equal(options.method, "PATCH");
+    assert.equal(options.headers["If-Match"], '"7"');
+    assert.deepEqual(JSON.parse(options.body), { title: "新名称", description: "Keep this", content });
+    return null;
+  }, "space", "board", " 新名称 ");
+  assert.deepEqual(calls, ["workspaces/space/materials/board", "workspaces/space/materials/board"]);
+  assert.equal(renamed.title, "新名称");
+  assert.equal(renamed.version, 8);
+});
+
+test("rename rejects empty or oversized names without any API calls", async () => {
+  for (const name of ["   ", "字".repeat(101)]) {
+    await assert.rejects(renameBoard(() => assert.fail("unexpected API call"), "space", "board", name), /invalid_title/);
+  }
+});
+
+test("rename surfaces a version conflict without retrying or overwriting", async () => {
+  let patches = 0;
+  await assert.rejects(renameBoard(async (_path, options) => {
+    if (!options) return { id: "board", workspace_id: "space", kind: "board", title: "Old", version: 1 };
+    patches++;
+    throw new Error("version_conflict");
+  }, "space", "board", "New"), /version_conflict/);
+  assert.equal(patches, 1);
+});