feat: side-thread task kind (Muse role alignment phase 2)

Tasks gain kind='main'|'side' (NULL=main). A side thread hangs under a
parent task, defaults to the local executor, never builds a worktree,
branch or container unless explicitly asked, and writes its conclusion
back to the parent via task_followups on terminal transition.

- server: kind validation + side-thread gates (parent required, no
  coordinator_parts/upload_id/environment_id, parent must not be a
  coordinator), local executor default, GET /tasks kind filter,
  /worktree 404 and /fork /merge /pr 409 for side threads.
- worker: side-default shunt in _run_attempt (no-worktree scratch cwd,
  in-memory plan=1 when a repo is present, seed/checkpoint skipped),
  _writeback_side_thread, marker task-create kind field + inheritance,
  side threads excluded from marker spawn counts.
- host/sandbox: --no-worktree plumbing for dispatch/goal/popen
  (Local + Docker), scratch cwd work/side-threads/<task-id>.
- console (classic only): kind filter + [旁聊] rows + '开旁聊' entry,
  side-thread dispatch mode, side-thread list in detail, merge/PR/fork
  hidden for side threads; build exit 0, console.html sha df39db5a.
- tests: new test_sidethread.py (29 tests) + kind backfill tests in
  test_p2_migrations.py; full cloud suite 3900 tests OK (skipped=13).

Design: verification/codex-muse-role-alignment-design-20261108.md
Summary: verification/codex-muse-role-align-p1p2-20261108.md
Local only: not pushed, not merged, not deployed.

cloud/console-react/src/hooks/useTaskDetail.ts

@@ -19,6 +19,9 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
   const [forkVisible, setForkVisible] = useState(false);
   const [forkMsg, setForkMsg] = useState("");
   const [coordChildren, setCoordChildren] = useState<Task[]>([]);
+  // 旁聊（Muse 角色对齐 P2）：当前任务挂着的旁聊线程（kind=side
+  // 且 parent_task_id=本任务），与协调员子任务同款拉取方式。
+  const [sideThreads, setSideThreads] = useState<Task[]>([]);
   const [agents, setAgents] = useState<Agent[]>([]);
   const [agentsNote, setAgentsNote] = useState("");
   const [reviews, setReviews] = useState<Review[]>([]);
@@ -71,6 +74,13 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
     } catch { setCoordChildren([]); }
   }, []);
 
+  const loadSideThreads = useCallback(async (task: Task) => {
+    try {
+      const d = await api<{ tasks: Task[] }>(paths.tasksByParent(task.project_id || "", task.id, "side"));
+      setSideThreads(d.tasks || []);
+    } catch { setSideThreads([]); }
+  }, []);
+
   const loadCost = useCallback(async (taskId: string) => {
     try {
       const c = await api<TaskCost>(paths.taskCost(taskId));
@@ -248,6 +258,7 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
       void startTrace(taskId, t.status);
       void loadAgents(taskId);
       void loadCoordChildren(t);
+      void loadSideThreads(t);
       void loadChatHistory(taskId);
       void loadFollowups(taskId);
       void loadPeerMessages(taskId);
@@ -259,7 +270,7 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
       setCurrentTask(null);
       setDetailBody("加载失败：" + e.message);
     }
-  }, [stopTrace, startTrace, loadAgents, loadCoordChildren, loadChatHistory, loadFollowups, loadPeerMessages, loadThread, loadThreads, loadReviews, loadApprovals, loadCost, getRole]);
+  }, [stopTrace, startTrace, loadAgents, loadCoordChildren, loadSideThreads, loadChatHistory, loadFollowups, loadPeerMessages, loadThread, loadThreads, loadReviews, loadApprovals, loadCost, getRole]);
 
   const refreshDetailLists = useCallback(async () => {
     const t = currentTaskRef.current;
@@ -277,12 +288,13 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
     void loadReviews(t.id);
     void loadApprovals(t.id);
     void loadCoordChildren(t);
+    void loadSideThreads(t);
     void loadAgents(t.id);
     void loadPeerMessages(t.id);
     void loadThread(t.id);
     void loadThreads(t.id);
     void loadCost(t.id);
-  }, [loadFollowups, loadChatHistory, loadReviews, loadApprovals, loadCoordChildren, loadAgents, loadPeerMessages, loadThread, loadThreads, loadCost]);
+  }, [loadFollowups, loadChatHistory, loadReviews, loadApprovals, loadCoordChildren, loadSideThreads, loadAgents, loadPeerMessages, loadThread, loadThreads, loadCost]);
 
   const doAction = useCallback(async (kind: string) => {
     const t = currentTaskRef.current;
@@ -423,7 +435,7 @@ export function useTaskDetail(getRole: (pid?: string) => string | null, onTasksR
 
   return {
     currentTask, detailBody, actionMsg, actionReasons, costBox, costSummary, forkVisible, setForkVisible, forkMsg,
-    coordChildren, agents, agentsNote, reviews, reviewMsg, reviewError, traceEntries, traceNote, traceDone,
+    coordChildren, sideThreads, agents, agentsNote, reviews, reviewMsg, reviewError, traceEntries, traceNote, traceDone,
     traceKind, setTraceKind, traceMsg, followups, approvals, approvalMsg, peerMessages, peerMsg,
     threadText, threadGateNote, threadMsg, threadList, chatMsg, chatHistory,
     showDetail, refreshDetailLists, doAction, taskCost, forkTask, postReview, submitFindings,