그림은 없던 게 아니라 묻혀 있었어

HEAD_CARDS = 12                  # the visible region
IMAGE_FLOOR = 8                  # how many of it may carry pictures
IMAGE_FLOOR_WINDOW_HOURS = 24.0  # never promote a stale picture


def apply_image_floor(rows: list[dict], limit: int) -> list[dict]:
    """Let pictures reach the head, without letting stale ones in.

    Zero requests: the pictures already exist on rows a purely
    chronological shelf buries, because a broad query source emits
    hundreds of items a day and a specialist publication a few dozen.
    """
    screen = min(HEAD_CARDS, limit)      # the SCREEN, not the page
    head = rows[:screen]
    have = sum(1 for r in head if r.get("image_url"))
    if have >= IMAGE_FLOOR:
        return rows                      # already fine: promote nothing

    now = datetime.now(timezone.utc)
    fresh = [r for r in rows
             if r.get("image_url")
             and _age_hours(r, now) <= IMAGE_FLOOR_WINDOW_HOURS][:IMAGE_FLOOR]
    if len(fresh) <= have:
        return rows                      # nothing fresher to promote

    picked = {r["id"] for r in fresh}
    keep = list(fresh)
    for row in head:                     # backfill the rest of the screen
        if len(keep) >= screen:
            break
        if row["id"] not in picked:
            keep.append(row)
            picked.add(row["id"])

    keep.sort(key=lambda r: _age_hours(r, now))   # still newest-first
    was_on_screen = {r["id"] for r in head}
    for row in keep:
        if row["id"] not in was_on_screen:
            row["promoted"] = True       # say what you moved
    return keep + rows[screen:]