refactor: 以 bzzoiro 为唯一数据源的全面重构

数据源统一为 bzzoiro,移除 Understat 与 injuries:
- 删除 src/data/understat.py / injuries.py 及相关测试
- 删除 injuries 模型与表;扩展 match_stats(xG 之外增加 big_chances/fouls)
- 新增 standings 表(联赛积分榜:位置/积分/xG/走势/分区)
- matches 表增加 source_event_id 血缘列,支撑统计回填

采集管线(bzzoiro 三条管线):
- events:赛程/比分(/events/),记录 source_event_id
- standings:积分榜快照(/leagues/{id}/standings/)
- stats:已完赛比赛详细统计回填(/events/{id}/stats/)

预测增强:
- standings_slice 替代 injuries_slice;积分榜专家替代阵容完整性专家
- AGENT_META runtime_config 同步更新

管理后台:
- ingest 路由重写为单一 bzzoiro 入口 + task 参数(events/standings/stats/all)
- 新增 /admin/data-completeness 数据完整性分析 API
- 数据源状态页简化为 bzzoiro 单源

前端:
- 采集页重构为任务驱动(比赛/积分榜/统计回填/全量)
- 新增「数据完整性」可视化页(覆盖率矩阵/字段完整率/健康摘要)
- 新增主站积分榜页(/standings)与比赛详情完整统计面板
- agent 名称同步更新(injuries→standings)

迁移 0015_bzzoiro_single_source 已在容器内验证通过,后端测试全部通过。

Co-Authored-By: new-provider/LongCat-2.0 <<EMAIL>>

src/data/normalize.py

@@ -219,35 +219,3 @@ def normalize_bzzoiro(raw: dict, league_type: str) -> NormalizedMatch | None:
     if m.match_status == "finished" and m.home_goals is None:
         m.match_status = "scheduled"
     return m
-
-
-def normalize_understat(raw: dict, league_type: str) -> NormalizedMatch | None:
-    """understat 单场 → NormalizedMatch(仅 xG)。"""
-    from src.data.team_names import normalize as normalize_name
-
-    dt_str = raw.get("datetime") or raw.get("date")
-    if not dt_str:
-        return None
-    dt = _parse_date(dt_str)
-    if dt is None:
-        return None
-    home_info = raw.get("h", {})
-    away_info = raw.get("a", {})
-    home_name = home_info.get("title", "") if isinstance(home_info, dict) else ""
-    away_name = away_info.get("title", "") if isinstance(away_info, dict) else ""
-    home = normalize_name(home_name)
-    away = normalize_name(away_name)
-    if not home or not away or home == away:
-        return None
-    home_xg = _to_float(raw["xG"].get("h")) if isinstance(raw.get("xG"), dict) else None
-    away_xg = _to_float(raw["xG"].get("a")) if isinstance(raw.get("xG"), dict) else None
-    return NormalizedMatch(
-        league_type=league_type,
-        date=dt,
-        home_team=home,
-        away_team=away,
-        match_status="finished",
-        season_label=derive_season_label(dt),
-        home_xg=home_xg,
-        away_xg=away_xg,
-    )