feat(signal_v2): scheduler + 5 unit tests

Time-window dispatcher: pre-market (07:00-09:00, 5min), market
(09:00-15:30, 1min), post-market (15:30-20:00, 5min), overnight skip
to next market day 07:00. Weekend + holiday detection via holidays.json.

Stub holidays.json with 13 dates. Task 6 will sync from
web-backend/stock/app/holidays.json.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

signal_v2/holidays.json

@@ -0,0 +1,15 @@
+[
+  "2026-01-01",
+  "2026-02-16",
+  "2026-02-17",
+  "2026-03-01",
+  "2026-05-05",
+  "2026-06-06",
+  "2026-08-15",
+  "2026-09-25",
+  "2026-09-26",
+  "2026-09-27",
+  "2026-10-03",
+  "2026-10-09",
+  "2026-12-25"
+]

signal_v2/scheduler.py

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+"""Polling scheduler — 시간대별 분기 + 휴장일 처리."""
+from __future__ import annotations
+import json
+import logging
+from datetime import datetime, timedelta, time
+from pathlib import Path
+from zoneinfo import ZoneInfo
+
+logger = logging.getLogger(__name__)
+
+KST = ZoneInfo("Asia/Seoul")
+_HOLIDAYS_PATH = Path(__file__).parent / "holidays.json"
+_HOLIDAYS: set[str] = set(json.loads(_HOLIDAYS_PATH.read_text(encoding="utf-8")))
+
+# Market windows
+_PRE_OPEN = time(7, 0)
+_OPEN = time(9, 0)
+_CLOSE = time(15, 30)
+_POST_END = time(20, 0)
+
+
+def _is_market_day(now: datetime) -> bool:
+    """평일 + 휴장일 아닌 날."""
+    if now.weekday() >= 5:  # Sat/Sun
+        return False
+    return now.strftime("%Y-%m-%d") not in _HOLIDAYS
+
+
+def _is_polling_window(now: datetime) -> bool:
+    """현재 시각이 폴링 윈도우 (07:00-20:00) 안인가."""
+    return _PRE_OPEN <= now.time() < _POST_END
+
+
+def _next_interval(now: datetime) -> float:
+    """다음 폴링까지 sleep 초수."""
+    if not _is_market_day(now):
+        return _seconds_until_next_market_open(now)
+
+    t = now.time()
+    if _PRE_OPEN <= t < _OPEN:
+        return 300.0
+    elif _OPEN <= t < _CLOSE:
+        return 60.0
+    elif _CLOSE <= t < _POST_END:
+        return 300.0
+    else:
+        return _seconds_until_next_market_open(now)
+
+
+def _seconds_until_next_market_open(now: datetime) -> float:
+    """다음 영업일의 07:00 KST 까지 초수."""
+    candidate = now.replace(hour=7, minute=0, second=0, microsecond=0)
+    if candidate <= now:
+        candidate += timedelta(days=1)
+
+    for _ in range(14):  # safety bound (max 2 weeks of holidays)
+        if _is_market_day(candidate):
+            return (candidate - now).total_seconds()
+        candidate += timedelta(days=1)
+
+    logger.warning("could not find next market day within 14 days; using +1 day")
+    return 86400.0

signal_v2/tests/test_scheduler.py

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+"""Tests for scheduler interval logic."""
+from datetime import datetime
+
+import pytest
+
+from signal_v2.scheduler import _next_interval, _is_market_day, KST
+
+
+def _kst(year, month, day, hour, minute=0):
+    return datetime(year, month, day, hour, minute, tzinfo=KST)
+
+
+def test_next_interval_pre_market_5min():
+    now = _kst(2026, 5, 18, 8, 30)  # Monday 08:30
+    assert _next_interval(now) == 300
+
+
+def test_next_interval_market_open_1min():
+    now = _kst(2026, 5, 18, 10, 0)  # Monday 10:00
+    assert _next_interval(now) == 60
+
+
+def test_next_interval_post_market_5min():
+    now = _kst(2026, 5, 18, 17, 0)  # Monday 17:00
+    assert _next_interval(now) == 300
+
+
+def test_next_interval_overnight_skip_to_next_morning():
+    now = _kst(2026, 5, 18, 22, 0)  # Monday 22:00
+    interval = _next_interval(now)
+    # Next polling: Tuesday 07:00 (9 hours away)
+    assert 9 * 3600 - 60 < interval < 9 * 3600 + 60
+
+
+def test_next_interval_holiday_skip():
+    # 2026-05-05 어린이날 (Tuesday holiday)
+    now = _kst(2026, 5, 5, 10, 0)
+    assert _is_market_day(now) is False
+    interval = _next_interval(now)
+    # Next: 2026-05-06 (Wed) 07:00, ~21h away
+    assert 20 * 3600 < interval < 22 * 3600