feat: 拆分 wecom_shown_keys 与 movement_baseline 历史层

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

daily/delta.py

@@ -15,6 +15,15 @@ logger = logging.getLogger(__name__)
 KeyFn = Callable[[dict[str, Any]], str]
 
 
+RECENT_BOARD_KEYS = (
+    "skills_trending",
+    "skills_hot",
+    "github_trending",
+    "github_emerging",
+    "github_topic",
+)
+
+
 def compare_depth() -> int:
     return env_int("DAILY_DELTA_COMPARE_DEPTH", 15)
 
@@ -39,6 +48,23 @@ def _key_set(items: list[dict[str, Any]], key_fn: KeyFn, *, depth: int) -> set[s
     return {key_fn(item) for item in items[:depth] if key_fn(item)}
 
 
+def load_recent_board_keys(
+    date_str: str,
+    *,
+    lookback_days: int | None = None,
+) -> dict[str, set[str]]:
+    """近 N 天各榜已展示过的 skill id / repo（不含当日，供补榜去重）。
+
+    委托 board_history.load_recent_shown_keys，只读 wecom_shown_keys，
+    不读 movement_baseline。
+    """
+    from daily.board_history import load_recent_shown_keys
+    from daily.config import board_dedup_days
+
+    days = lookback_days if lookback_days is not None else board_dedup_days()
+    return load_recent_shown_keys(date_str, lookback_days=days)
+
+
 def find_previous_data(date_str: str) -> tuple[str, dict[str, Any]] | None:
     """查找最近一份早于 date_str 的 data.json。"""
     try: