fix: 日报摘要可靠性(去模型兜底+重试) 与取数逻辑优化

- llm/client: 移除内置默认模型兜底(deepseek-chat/qwen-plus), 模型必须显式配置否则报错
- reporter._llm_call: 指数退避重试(LLM_RETRY_TIMES 默认3 / LLM_RETRY_BACKOFF_SEC 默认2s)
- pipeline report: report_date 改为当天(原昨天+回溯3天)
- reporter._collect_news_events: 读当天+前一天目录, publish_time 30h 回溯(NEWS_LOOKBACK_HOURS=30), 统一时区
- reporter._collect_xwlb: 固定取 day_str 前一日(已播出联播), source_date 同步
- 公告/调研/互动保持近15日设置(CNINFO_DAYS_BACK), 不受 30h 影响
- 测试: 新增 30h回溯/带时区/重试/模型缺失/xwlb 前一日 用例

tests/test_llm.py

@@ -322,21 +322,24 @@ async def test_extract_event_async_retries(fake_config: LLMConfig) -> None:
 def test_load_llm_config_deepseek_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("LLM_PROVIDER", "deepseek")
     monkeypatch.setenv("DEEPSEEK_API_KEY", "sk-test-deepseek")
+    monkeypatch.setenv("DEEPSEEK_MODEL", "deepseek-v4-flash")
     monkeypatch.delenv("LLM_MODEL", raising=False)
     cfg = load_llm_config()
     assert cfg.provider == "deepseek"
     assert cfg.api_key == "sk-test-deepseek"
-    assert cfg.model.startswith("deepseek")
+    assert cfg.model == "deepseek-v4-flash"
     assert "deepseek" in cfg.base_url
 
 
 def test_load_llm_config_qwen_from_env(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setenv("LLM_PROVIDER", "qwen")
     monkeypatch.setenv("DASHSCOPE_API_KEY", "sk-test-qwen")
+    monkeypatch.setenv("QWEN_MODEL", "qwen-plus")
     monkeypatch.delenv("LLM_MODEL", raising=False)
     cfg = load_llm_config()
     assert cfg.provider == "qwen"
     assert cfg.api_key == "sk-test-qwen"
+    assert cfg.model == "qwen-plus"
     assert "dashscope" in cfg.base_url or "aliyuncs" in cfg.base_url
 
 
@@ -347,5 +350,15 @@ def test_load_llm_config_unknown_provider_raises(monkeypatch: pytest.MonkeyPatch
 
 def test_load_llm_config_missing_key_raises(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.delenv("DEEPSEEK_API_KEY", raising=False)
-    with pytest.raises(ValueError):
+    monkeypatch.setenv("DEEPSEEK_MODEL", "deepseek-v4-flash")
+    with pytest.raises(ValueError, match="API key"):
+        load_llm_config(provider="deepseek")
+
+
+def test_load_llm_config_missing_model_raises(monkeypatch: pytest.MonkeyPatch) -> None:
+    """去掉内置默认模型后：未显式配置模型必须报错（不再回退 deepseek-chat）。"""
+    monkeypatch.setenv("DEEPSEEK_API_KEY", "sk-test")
+    monkeypatch.delenv("DEEPSEEK_MODEL", raising=False)
+    monkeypatch.delenv("LLM_MODEL", raising=False)
+    with pytest.raises(ValueError, match="模型"):
         load_llm_config(provider="deepseek")