feat(cli): time --tz 时区偏移（默认本机时区的修正项），151 测试全绿

src/ppclock/cli.py

@@ -103,6 +103,7 @@ def build_parser() -> argparse.ArgumentParser:
 
     sp = sub.add_parser("time", help="对时（默认当前本地时间）")
     sp.add_argument("datetime", nargs="?", help="ISO8601，如 2026-07-24T15:30:00")
+    sp.add_argument("--tz", type=float, help="时区偏移（小时，如 8=北京；仅无显式时间时生效）")
 
     sp = sub.add_parser("mode", help="显示模式")
     sp.add_argument("name", choices=sorted(P.MODES))
@@ -191,6 +192,9 @@ async def _run_command(args, t):
     if c == "time":
         dt = (datetime.datetime.fromisoformat(args.datetime)
               if args.datetime else None)
+        if dt is None and args.tz is not None:
+            tz = datetime.timezone(datetime.timedelta(hours=args.tz))
+            dt = datetime.datetime.now(tz).replace(tzinfo=None)
         await C.set_time(t, dt)
         return {"set": (dt or datetime.datetime.now()).isoformat()}
     if c == "mode":

tests/test_cli.py

@@ -286,3 +286,17 @@ class TestViaBridge:
         code, _ = run_cli(capsys, ["--json", "scan"])
         assert code == 0
         assert called["args"] == ("10.0.0.7", 8971)
+
+
+class TestTimeTz:
+    def test_tz_offset_applied(self, capsys, monkeypatch):
+        """--tz 8 应写入北京墙钟（与系统 UTC 本地时相差 8h）"""
+        import datetime as _dt
+        code, out = run_cli(capsys, ["--json", "time", "--tz", "8"])
+        assert code == 0
+        sent = FakeTransport.instances[0].rxtx_writes[0]
+        # dd 帧的 unix 字段（本地墙钟按 UTC 计）反解小时
+        unix_local = int.from_bytes(sent[1:5], "big")
+        wall = _dt.datetime.fromtimestamp(unix_local, _dt.timezone.utc)
+        utc_now = _dt.datetime.now(_dt.timezone.utc)
+        assert abs((wall - utc_now).total_seconds() - 8 * 3600) < 120