code-to10 goal live update: POST /tasks/{id}/goal updates a running goal loop at the next round boundary

Server writes goal + monotonic goal_version + task_goal_history in one
transaction (CAS on version, approve_merge only, new-semantic goal tasks
only, terminal/merged 409, same-goal noop). Worker mirror thread (30s)
and breakpoint-resume claim hook write the update as a signal file next
to host-state.json; host run_goal_loop applies it at round boundaries
(top of round and before the declaration check, so a declaration made
for the old goal in a turn during which the goal changed is voided),
with an explicit old->new notice, same thread/worktree, rounds/usage/
budget/failed counters untouched. handler method accounting is a
contract update: 239 total / 223 mixins / 16 in server.py.

(cherry picked from commit 6841f287219d2b36cfbb8803642344b84dae4377)

Reconcile-port: handler_lifecycle.py contents redirected — _update_goal_task method + _goal_update_reject/_goal_signal_status pure functions + goal_live_update import into cloud/server.py (target keeps 6-mixin split); _task_to_dict goal fields into cloud/handler_support.py; migrate columns into cloud/server.py migrate_tasks_table; test patch target handler_lifecycle→server; test_handler_split_conformance.py kept at target version, to be re-pinned for the unified line in a final commit.

cloud/handler_support.py

@@ -154,6 +154,11 @@ def _task_to_dict(row, attachments=None, total_tokens=None):
         "verify_command": _row_get(row, "verify_command"),
         "goal_max_rounds": _row_get(row, "goal_max_rounds"),
         "goal_mode": _row_get(row, "goal_mode") or 0,
+        # 运行中改 goal：goal_version 是已提交版本（服务端写库），
+        # applied_goal_version 是 host 循环已应用版本（镜像回写），
+        # 两者不等时说明信号在途或未到轮次边界，绝不能冒充已应用。
+        "goal_version": _row_get(row, "goal_version") or 0,
+        "applied_goal_version": _row_get(row, "applied_goal_version") or 0,
         "attachments": list(attachments or []),
         "resume_message": _row_get(row, "resume_message"),
         "worktree_host": _row_get(row, "worktree_host"),