长任务 P0 三件：断点进库、错误分类+熔断、Run/Step 时间线

断点进库：task_checkpoints 表（PG 新库 + 老库幂等补表 + 迁移清单
对齐）；worker 在 goal 任务执行期间每 30 秒把磁盘 host-state 断点
镜像进库，终局再补一次；断点续跑认领前，若 host-state 条目丢失
但库里有断点，先按库断点重建最小条目再跑，库里也没有断点时不
造假、走原有拒绝路径。

错误分类+熔断：sandbox 四处解析加永久错误分支（KeyError、配置
缺失等无结论异常退出判 failed 死信，不再判 interrupted；host 已
明言 interrupted 的不受影响，未知错误不分类）；worker 自动恢复
加退避（10 秒起指数退避、封顶 300 秒）与无进展熔断（库断点轮次
连续 3 次不变即标 auto_resume_stalled 等人工）。

时间线：task_steps 表 + host 每轮写 host-steps 步骤文件 + worker
导入；GET /tasks/{id}/timeline 一次返回 steps 与 checkpoints；
认领、暂停、自动恢复、终局都记步骤。旧任务返回空数组，不编造。

单测：cloud/tests/test_p0_three.py 14 项（分类、熔断、镜像重建、
步骤导入去重、timeline 接口）。

cloud/sandbox.py

@@ -117,6 +117,57 @@ def _parse_goal_output(stdout):
     return None, None
 
 
+# P0 三件其二：goal 错误签名。permanent = 同代码、同断点、同配置
+# 下重试必然再失败（断点丢失、配置缺失、旧语义误用），必须判
+# failed 终态进死信，绝不能判 interrupted 进自动恢复；transient =
+# 网络/网关抖动，重试有意义，走原有 interrupted 路径。未知错误
+# 不分类（None），走原有逻辑，兜底靠 worker 的无进展熔断。
+_GOAL_PERMANENT_MARKERS = (
+    "goal-resume 拒绝",
+    "KeyError",
+    "没有会话线程",
+    "没有 goal 记录",
+    "provider not found",
+    "Model provider",
+    "Missing environment variable",
+    "任务已存在",
+)
+_GOAL_TRANSIENT_MARKERS = (
+    "timed out",
+    "Timeout",
+    "429",
+    "502",
+    "503",
+    "RemoteDisconnected",
+    "IncompleteRead",
+    "Connection reset",
+    "connection refused",
+)
+
+
+def _classify_goal_error(stdout, stderr):
+    """返回 (kind, snippet)：kind 为 permanent/transient/None。
+
+    snippet 取命中标记所在行（截 500 字），供终态 error_text 用；
+    命中多个时 permanent 优先于 transient（永久错误里常混着
+    网络字样，反过来会把死信误判成可重试）。
+    """
+    combined = (stdout or "") + "\n" + (stderr or "")
+    for marker in _GOAL_PERMANENT_MARKERS:
+        if marker in combined:
+            for line in combined.splitlines():
+                if marker in line:
+                    return "permanent", line.strip()[:500]
+            return "permanent", marker
+    for marker in _GOAL_TRANSIENT_MARKERS:
+        if marker in combined:
+            for line in combined.splitlines():
+                if marker in line:
+                    return "transient", line.strip()[:500]
+            return "transient", marker
+    return None, None
+
+
 def _goal_resume_refusal(stdout):
     """host.py goal-resume 的拒绝行（断点丢失时），无则返回 None。
 
@@ -584,6 +635,8 @@ class LocalExecutor(Executor):
         interrupted_reason = _goal_interrupted_reason(stdout_full)
         refusal = _goal_resume_refusal(stdout_full)
         combined = stdout_full + stderr
+        perm_kind, perm_snippet = _classify_goal_error(
+            stdout_full, stderr)
         if refusal is not None and met is None:
             # 断点丢失拒绝：终态 failed，不进自动恢复（见 helper）。
             met, goal_error = None, refusal
@@ -601,6 +654,14 @@ class LocalExecutor(Executor):
             status = "interrupted"
             goal_error = (interrupted_reason
                           or "host goal 异常中断，断点可续跑")
+        elif (met is None and returncode != 0
+                and perm_kind == "permanent"):
+            # P0 三件其二：永久错误（断点 KeyError、配置缺失等）
+            # 的无结论异常退出——同代码同断点重试必然再失败，
+            # 判 failed 终态进死信，绝不判 interrupted 空转。
+            # host 已明言 interrupted 的在上一分支，不受影响。
+            status = "failed"
+            goal_error = perm_snippet or "goal 永久错误"
         elif returncode != 0:
             if met is None:
                 # 无结论的异常退出（进程被杀、连接断后恢复时抛错
@@ -1301,6 +1362,8 @@ class DockerExecutor(Executor):
         met, goal_error = _parse_goal_output(stdout_full)
         interrupted_reason = _goal_interrupted_reason(stdout_full)
         combined = stdout_full + stderr
+        perm_kind, perm_snippet = _classify_goal_error(
+            stdout_full, stderr)
         if "已存在" in combined:
             met, goal_error = None, (
                 "host 任务已存在：goal 失败请用继续而非重试——"
@@ -1314,6 +1377,13 @@ class DockerExecutor(Executor):
             status = "interrupted"
             goal_error = (interrupted_reason
                           or "host goal 异常中断，断点可续跑")
+        elif (met is None and returncode != 0
+                and perm_kind == "permanent"):
+            # P0 三件其二：永久错误无结论异常退出 → failed 死信
+            # （同 local 侧注释；host 已明言 interrupted 的在上
+            # 一分支，不受影响）。
+            status = "failed"
+            goal_error = perm_snippet or "goal 永久错误"
         elif returncode != 0:
             if met is None:
                 # 无结论的异常退出（进程被杀、连接断后恢复时抛错
@@ -1407,6 +1477,8 @@ class DockerExecutor(Executor):
         met, goal_error = _parse_goal_output(stdout_full)
         interrupted_reason = _goal_interrupted_reason(stdout_full)
         refusal = _goal_resume_refusal(stdout_full)
+        perm_kind, perm_snippet = _classify_goal_error(
+            stdout_full, stderr)
         if refusal is not None and met is None:
             # 断点丢失拒绝：终态 failed，不进自动恢复（见 helper）。
             status = "failed"
@@ -1417,6 +1489,13 @@ class DockerExecutor(Executor):
             status = "interrupted"
             goal_error = (interrupted_reason
                           or "host goal-resume 异常中断，断点可续跑")
+        elif (met is None and returncode != 0
+                and perm_kind == "permanent"):
+            # P0 三件其二：续跑侧永久错误（典型如断点 KeyError）
+            # → failed 死信；任务 2 的 12 秒空转就是此分支缺失
+            # 造成的（当时无结论异常退出被判 interrupted）。
+            status = "failed"
+            goal_error = perm_snippet or "goal 永久错误"
         elif returncode != 0:
             if met is None:
                 # 无结论的异常退出：断点在盘上，记 interrupted
@@ -1508,6 +1587,8 @@ class DockerExecutor(Executor):
         met, goal_error = _parse_goal_output(stdout_full)
         interrupted_reason = _goal_interrupted_reason(stdout_full)
         refusal = _goal_resume_refusal(stdout_full)
+        perm_kind, perm_snippet = _classify_goal_error(
+            stdout_full, stderr)
         if refusal is not None and met is None:
             # 断点丢失拒绝：终态 failed，不进自动恢复（见 helper）。
             status = "failed"
@@ -1518,6 +1599,11 @@ class DockerExecutor(Executor):
             status = "interrupted"
             goal_error = (interrupted_reason
                           or "host goal-resume 异常中断，断点可续跑")
+        elif (met is None and returncode != 0
+                and perm_kind == "permanent"):
+            # P0 三件其二：续跑侧永久错误 → failed 死信（同上）。
+            status = "failed"
+            goal_error = perm_snippet or "goal 永久错误"
         elif returncode != 0:
             if met is None:
                 # 无结论的异常退出：断点在盘上，记 interrupted