feat: LLM/Embedding 重试次数纳入 system.yaml 统一配置

- system.yaml: llm.max_retries(死配置) 改为 llm.max_attempts；embedding 段新增 max_attempts
- llm/client.py: LLMConfig 新增 max_attempts（默认 3 兜底），load_llm_config 读取配置
- llm/extractor.py: translate_and_extract(_async) max_attempts=None 时取 config.max_attempts
- embedding/client.py: load_embedding_config 读取 embedding.max_attempts
- scheduler/reporter.py: _call_llm_simple max_retries=None 时取 max_attempts-1
- 新增 2 个配置读取测试；已同步 pi5 验证

tests/test_embedding.py

@@ -87,6 +87,12 @@ class TestLoadEmbeddingConfig:
         assert cfg.provider == "dashscope"
         assert cfg.api_key == "sk-dashscope-test"
 
+    def test_max_attempts_from_system_yaml(self, monkeypatch):
+        """重试次数取自 system.yaml embedding.max_attempts（当前 3）。"""
+        monkeypatch.setenv("DASHSCOPE_API_KEY", "sk-dashscope-test")
+        cfg = load_embedding_config()
+        assert cfg.max_attempts == 3
+
     def test_fallback_to_qwen_key(self, monkeypatch):
         monkeypatch.delenv("DASHSCOPE_API_KEY", raising=False)
         monkeypatch.setenv("QWEN_API_KEY", "sk-qwen-key")