feat: show force-close badge and countdown when FORCE_CLOSE is enabled

Add shared lib/UI for midnight force-close indicator on instance and hub pages, and document Gate intraday 0-point exit alignment.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_force_close_lib.py

@@ -0,0 +1,57 @@
+from datetime import datetime
+from zoneinfo import ZoneInfo
+
+from lib.trade.force_close_lib import (
+    build_force_close_state,
+    compute_next_force_close_at_ms,
+    force_close_label,
+    format_force_close_countdown,
+    is_force_close_active_hour,
+)
+
+TZ = ZoneInfo("Asia/Shanghai")
+
+
+def _ms(y, m, d, hh, mm=0):
+    return int(datetime(y, m, d, hh, mm, tzinfo=TZ).timestamp() * 1000)
+
+
+def test_force_close_label():
+    assert force_close_label(0) == "强制清仓 00:00"
+    assert force_close_label(8) == "强制清仓 08:00"
+
+
+def test_next_force_close_at_midnight():
+    # 2026-07-05 23:30 -> next 2026-07-06 00:00
+    now = _ms(2026, 7, 5, 23, 30)
+    assert compute_next_force_close_at_ms(bj_hour=0, now_ms=now, tz_name="Asia/Shanghai") == _ms(
+        2026, 7, 6, 0, 0
+    )
+
+
+def test_next_force_close_same_day_before_hour():
+    now = _ms(2026, 7, 6, 15, 0)
+    assert compute_next_force_close_at_ms(bj_hour=0, now_ms=now, tz_name="Asia/Shanghai") == _ms(
+        2026, 7, 7, 0, 0
+    )
+
+
+def test_active_hour_and_countdown():
+    now = _ms(2026, 7, 6, 0, 15)
+    assert is_force_close_active_hour(0, now_ms=now, tz_name="Asia/Shanghai")
+    state = build_force_close_state(True, 0, now_ms=now, tz_name="Asia/Shanghai")
+    assert state["enabled"] is True
+    assert state["active"] is True
+    assert state["countdown"] == "执行中"
+    assert state["remaining_sec"] == 0
+
+
+def test_disabled_state():
+    state = build_force_close_state(False, 0)
+    assert state["enabled"] is False
+    assert state["next_at_ms"] is None
+
+
+def test_format_countdown():
+    assert format_force_close_countdown(3661) == "01:01:01"
+    assert format_force_close_countdown(0, active=True) == "执行中"