feat(cli): enter --forced-close-at 시간 기반 자동청산 옵션 (issue #17, BAT-024)

trex-core enter 에 --forced-close-at <ISO8601>(절대시간) 옵션 추가.
지정 시 buy intent payload 의 기존 forced_close_at 에 매핑(계약·도메인·
forced-close 루프 REQ-037 불변, CLI 노출 갭만 보완). 잘못된 형식은 제출
전 거부, 미지정 시 미포함(하위호환). 상대시간 옵션은 미채택.

REQ-032 change-req(CHG-20260609-01/02) → BAT-024(batch-lite) →
Implemented. 단위 353 passed, ruff clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/runtime/test_cli_operator.py

@@ -143,6 +143,32 @@ def test_enter_with_yes_submits_buy_intent():
     assert "symbol" not in p                  # server-resolved (dcy-011)
 
 
+def test_enter_with_forced_close_at_maps_to_payload():
+    # REQ-032 AC-5: --forced-close-at (absolute) → buy intent forced_close_at.
+    rpc = _RpcRecorder(_ADMITTED)
+    rc = cli.main(["enter", "PF-1", "--capital", "100000", "--yes",
+                   "--forced-close-at", "2026-06-09T15:20:00+09:00"], rpc=rpc)
+    assert rc == 0
+    p = rpc.calls[0]["payload"]
+    assert p["forced_close_at"] == "2026-06-09T15:20:00+09:00"
+
+
+def test_enter_without_forced_close_at_omits_field():
+    # REQ-032 AC-6: unspecified → field absent (backward compat).
+    rpc = _RpcRecorder(_ADMITTED)
+    rc = cli.main(["enter", "PF-1", "--capital", "100000", "--yes"], rpc=rpc)
+    assert rc == 0
+    assert "forced_close_at" not in rpc.calls[0]["payload"]
+
+
+def test_enter_rejects_malformed_forced_close_at_before_submit():
+    # REQ-032 AC-6: invalid timestamp rejected at CLI, no RPC submitted.
+    rpc = _RpcRecorder(_ADMITTED)
+    rc = cli.main(["enter", "PF-1", "--capital", "100000", "--yes",
+                   "--forced-close-at", "notatime"], rpc=rpc)
+    assert rc == 1 and rpc.calls == []
+
+
 def test_enter_rejected_returns_nonzero():
     rpc = _RpcRecorder(_REJECTED)
     rc = cli.main(["enter", "PF-x", "--yes"], rpc=rpc)