feat: 任务实时链路 SSE (#61)

host.py：回合通知摘要成链路条目，增量追加到 <state>/host-traces/<task>.jsonl（上限 5000 行）；dispatch/run/goal/delegate 设链路文件
cloud/server.py：GET /tasks/{id}/trace 快照 + /trace/stream SSE（snapshot → entry → done；worktree 在别机时空链路 + 说明）
console：详情链路区，运行中 fetch 流式渲染（EventSource 不能带 X-API-Key 头），终态走快照；DOM 上限 1000 条
单测：test_host_trace 7 + test_task_trace 6；host 49、cloud 525、deploy 14 全过

Co-authored-by: host <host@test.local>

tests/test_host_trace.py

@@ -0,0 +1,135 @@
+"""实时链路（host 侧）单测：通知摘要器 + 链路文件追加。
+
+不启动 app-server：Server 实例用 object.__new__ 绕开 __init__
+（__init__ 会拉起 codex 子进程），只测与进程无关的方法。
+"""
+
+import json
+import os
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+try:
+    import host
+    from host import Server, TRACE_MAX_LINES, _summarize_trace_item
+except ImportError:
+    sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+    import host
+    from host import Server, TRACE_MAX_LINES, _summarize_trace_item
+
+
+def _msg(item, ts=1700000000000):
+    return {"method": "item/completed",
+            "params": {"item": item, "completedAtMs": ts}}
+
+
+class SummarizeTraceItemTestCase(unittest.TestCase):
+    def test_exec_truncates_command(self):
+        entries = _summarize_trace_item(
+            "item/completed",
+            {"item": {"type": "commandExecution", "id": "c1",
+                      "command": "x" * 600, "cwd": "/w",
+                      "exitCode": 0, "durationMs": 12},
+             "completedAtMs": 1700000000000})
+        self.assertEqual(len(entries), 1)
+        self.assertEqual(entries[0]["kind"], "exec")
+        self.assertEqual(len(entries[0]["command"]), 500)
+        self.assertEqual(entries[0]["exitCode"], 0)
+        self.assertEqual(entries[0]["ts"], 1700000000000)
+
+    def test_file_change_split_per_change(self):
+        entries = _summarize_trace_item(
+            "item/completed",
+            {"item": {"type": "fileChange", "id": "f1", "status": "completed",
+                      "changes": [{"path": "a.py", "kind": "update"},
+                                  {"path": "b.py", "kind": "add"}]},
+             "startedAtMs": 1700000000001})
+        self.assertEqual([e["kind"] for e in entries], ["file", "file"])
+        self.assertEqual(entries[0]["id"], "f1:a.py")
+        self.assertEqual(entries[1]["path"], "b.py")
+
+    def test_message_reasoning_tool_call_plan(self):
+        cases = [
+            ({"type": "agentMessage", "id": "m1", "phase": "final",
+              "text": "done"}, "message"),
+            ({"type": "reasoning", "id": "r1",
+              "summary": ["a", "b"]}, "reasoning"),
+            ({"type": "mcpToolCall", "id": "t1", "server": "s",
+              "tool": "read", "status": "completed"}, "tool"),
+            ({"type": "functionCallOutput", "id": "o1",
+              "name": "read_file"}, "call"),
+            ({"type": "plan", "id": "p1", "text": "step"}, "plan"),
+        ]
+        for item, kind in cases:
+            entries = _summarize_trace_item("item/completed",
+                                            {"item": item})
+            self.assertEqual(len(entries), 1)
+            self.assertEqual(entries[0]["kind"], kind)
+
+    def test_skipped_notifications(self):
+        self.assertEqual(_summarize_trace_item(
+            "item/completed", {"item": {"type": "userMessage", "id": "u1",
+                                        "text": "hi"}}), [])
+        self.assertEqual(_summarize_trace_item(
+            "item/completed", {"item": {"type": "agentMessage", "id": "m2",
+                                        "text": ""}}), [])
+        self.assertEqual(_summarize_trace_item("item/completed", {}), [])
+        self.assertEqual(_summarize_trace_item(
+            "item/completed", {"item": {"type": "unknownThing",
+                                        "id": "z"}}), [])
+
+
+class TraceFileTestCase(unittest.TestCase):
+    def _bare_server(self):
+        srv = object.__new__(Server)
+        srv.trace_path = None
+        srv._trace_lines = 0
+        return srv
+
+    def test_set_trace_file_and_append(self):
+        with tempfile.TemporaryDirectory() as d:
+            state_path = os.path.join(d, "host-state.json")
+            srv = self._bare_server()
+            srv.set_trace_file(state_path, "abc/def?id=1")
+            self.assertEqual(
+                srv.trace_path,
+                os.path.join(d, "host-traces", "abc-def-id-1.jsonl"))
+            srv._append_trace(_msg({"type": "commandExecution", "id": "c1",
+                                    "command": "ls", "cwd": "/w",
+                                    "exitCode": 0, "durationMs": 3}))
+            srv._append_trace(_msg({"type": "userMessage", "id": "u1",
+                                    "text": "hi"}))
+            with open(srv.trace_path, encoding="utf-8") as f:
+                lines = f.read().strip().split("\n")
+            self.assertEqual(len(lines), 1)
+            self.assertEqual(json.loads(lines[0])["kind"], "exec")
+
+    def test_set_trace_file_failure_keeps_none(self):
+        with tempfile.TemporaryDirectory() as d:
+            # host-traces 已被普通文件占住，建目录失败时不抛、不影响回合。
+            blocker = os.path.join(d, "host-traces")
+            with open(blocker, "w", encoding="utf-8") as f:
+                f.write("x")
+            srv = self._bare_server()
+            srv.set_trace_file(os.path.join(d, "host-state.json"), "t1")
+            self.assertIsNone(srv.trace_path)
+
+    def test_append_stops_at_max_lines(self):
+        with tempfile.TemporaryDirectory() as d:
+            srv = self._bare_server()
+            srv.trace_path = os.path.join(d, "t.jsonl")
+            srv._trace_lines = TRACE_MAX_LINES - 1
+            srv._append_trace(_msg({"type": "commandExecution", "id": "c1",
+                                    "command": "a"}))
+            srv._append_trace(_msg({"type": "commandExecution", "id": "c2",
+                                    "command": "b"}))
+            with open(srv.trace_path, encoding="utf-8") as f:
+                lines = f.read().strip().split("\n")
+            self.assertEqual(len(lines), 1)
+            self.assertEqual(json.loads(lines[0])["id"], "c1")
+
+
+if __name__ == "__main__":
+    unittest.main()