chore: 死代码与重复逻辑清理

删除未引用/未调用符号:
- PredictionRepository(无引用)
- is_correct_1x2(无调用者)
- LeagueOut(路由用 list[dict])
- IngestResponse(IngestBzzoiroResponse 已替代)
- SecurityCheckError(从未 raise,assert_security_on_startup 用 sys.exit)
- short_write(仅自引用,全仓库无外部调用)
- fetchIngestJobs(列表函数无页面使用,单数 fetchIngestJob 仍保留)
- clear_prompt_cache(无入口)

去重:
- eval._actual_1x2 改为委托 utils.actual_1x2(单一权威源)

全量测试 270 通过,业务行为不变。

src/api/schemas.py

@@ -7,13 +7,6 @@ from typing import Any
 from pydantic import BaseModel, Field
 
 
-class LeagueOut(BaseModel):
-    id: int
-    code: str
-    name: str
-    country: str | None
-
-
 class MatchOut(BaseModel):
     id: int
     league_code: str | None
@@ -130,13 +123,6 @@ class TeamAliasOut(BaseModel):
     original_alias: str
 
 
-class IngestResponse(BaseModel):
-    leagues: dict
-    total_inserted: int
-    total_updated: int
-    errors: list[str] = []
-
-
 class IngestBzzoiroResponse(BaseModel):
     """POST /api/v1/ingest/bzzoiro 响应:兼容原 message 字段,新增 job_id 供轮询。"""