feat: tighten conversation folder archive projections

tests/conversation-home-items.test.ts

@@ -65,6 +65,157 @@ function buildImportedThreadProject(deviceId: string, id: string, folderName: st
   };
 }
 
+function buildThreadContextSnapshot(
+  projectId: string,
+  threadId: string,
+  title: string,
+  contextBudgetLevel: "safe" | "watch" | "urgent" | "critical",
+  mustFinishBeforeCompaction: boolean,
+  contextBudgetRemainingPct: number,
+  capturedAt: string,
+  nodeId: string,
+) {
+  return {
+    snapshotId: `${projectId}-${threadId}-snapshot`,
+    projectId,
+    taskId: `${projectId}-${threadId}-task`,
+    threadId,
+    title,
+    summary: `${title} 的线程状态`,
+    nodeId,
+    workerId: "worker-1",
+    sourceKind: "worker_estimator",
+    status: "context_urgent",
+    contextBudgetRemainingPct,
+    contextBudgetLevel,
+    mustFinishBeforeCompaction,
+    estimatedRemainingTurns: 4,
+    estimatedRemainingLargeMessages: 2,
+    compactionCount: 0,
+    patchPending: false,
+    testsPending: false,
+    evidencePending: false,
+    checklist: [],
+    capturedAt,
+  } satisfies import("../src/lib/boss-data").ThreadContextSnapshot;
+}
+
+test("folder archives use the latest thread preview/time while subtitle and context ring come from the right threads", async () => {
+  await setup();
+  const state = await readState();
+
+  state.projects = state.projects.filter((project) => project.id === "master-agent");
+  state.projects.push(
+    buildImportedThreadProject(
+      "mac-studio",
+      "boss-thread-latest",
+      "Boss",
+      "boss",
+      "最新线程",
+      "thread-latest",
+      "2026-04-04T12:00:00+08:00",
+    ),
+    buildImportedThreadProject(
+      "mac-studio",
+      "boss-thread-urgent",
+      "Boss",
+      "boss",
+      "优先收尾",
+      "thread-urgent",
+      "2026-04-04T11:00:00+08:00",
+    ),
+  );
+  state.threadContextSnapshots = [
+    buildThreadContextSnapshot(
+      "boss-thread-latest",
+      "thread-latest",
+      "最新线程",
+      "critical",
+      false,
+      12,
+      "2026-04-04T12:05:00+08:00",
+      "node-latest",
+    ),
+    buildThreadContextSnapshot(
+      "boss-thread-urgent",
+      "thread-urgent",
+      "优先收尾",
+      "critical",
+      true,
+      87,
+      "2026-04-04T11:05:00+08:00",
+      "node-urgent",
+    ),
+  ];
+
+  const folder = getConversationHomeItems(state).find((item) => item.conversationType === "folder_archive");
+
+  assert.ok(folder, "expected grouped folder archive item");
+  assert.equal(folder?.threadTitle, "Boss");
+  assert.equal(folder?.folderLabel, "2 个线程 · 最近：最新线程");
+  assert.equal(folder?.preview, "最近消息：最新线程");
+  assert.equal(folder?.lastMessagePreview, "最近消息：最新线程");
+  assert.equal(folder?.latestReplyAt, "2026-04-04T12:00:00+08:00");
+  assert.equal(folder?.latestReplyLabel, formatTimestampLabel("2026-04-04T12:00:00+08:00"));
+  assert.equal(folder?.contextBudgetIndicator.level, "critical");
+  assert.equal(folder?.contextBudgetIndicator.percent, 87);
+  assert.equal(folder?.mustFinishBeforeCompaction, true);
+  assert.equal(folder?.contextBudgetSourceNodeId, "node-urgent");
+  assert.equal(folder?.contextBudgetUpdatedAt, "2026-04-04T11:05:00+08:00");
+});
+
+test("conversation home upgrades and downgrades a folder archive as thread count crosses 1 and 2", async () => {
+  await setup();
+  const state = await readState();
+
+  state.projects = state.projects.filter((project) => project.id === "master-agent");
+  state.projects.push(
+    buildImportedThreadProject(
+      "mac-studio",
+      "boss-thread-1",
+      "Boss",
+      "boss",
+      "归档确认",
+      "thread-1",
+      "2026-04-04T10:00:00+08:00",
+    ),
+  );
+
+  let items = getConversationHomeItems(state);
+  let direct = items.find((item) => item.projectId === "boss-thread-1");
+
+  assert.ok(direct, "expected a single thread to remain direct");
+  assert.equal(direct?.conversationType, "single_device");
+
+  state.projects.push(
+    buildImportedThreadProject(
+      "mac-studio",
+      "boss-thread-2",
+      "Boss",
+      "boss",
+      "发布回滚",
+      "thread-2",
+      "2026-04-04T11:00:00+08:00",
+    ),
+  );
+
+  items = getConversationHomeItems(state);
+  const folder = items.find((item) => item.conversationType === "folder_archive" && item.folderKey === "mac-studio:boss");
+
+  assert.ok(folder, "expected folder archive once the folder has 2 threads");
+  assert.equal(folder?.threadCount, 2);
+  assert.equal(items.some((item) => item.projectId === "boss-thread-1"), false);
+  assert.equal(items.some((item) => item.projectId === "boss-thread-2"), false);
+
+  state.projects = state.projects.filter((project) => project.id !== "boss-thread-2");
+
+  items = getConversationHomeItems(state);
+  direct = items.find((item) => item.projectId === "boss-thread-1");
+
+  assert.ok(direct, "expected a single remaining thread to downgrade back to direct");
+  assert.equal(direct?.conversationType, "single_device");
+});
+
 test("conversation home groups multiple imported threads by folder while keeping single-thread projects direct", async () => {
   await setup();
   const state = await readState();