feat: 人设模板系统、节点调度标签、pydantic-settings收敛、错误处理增强

新增persona_template表和CRUD API，BaseIndividualModel增加node_affinity和template_origin_id字段，
WorkerCluster支持多集群Ray资源调度，环境变量收敛到pydantic-settings统一校验，
数据库异常转换为结构化BusinessError/RetryableError，系统节点支持custom_system_prompt。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

kilostar/api/__init__.py

@@ -21,6 +21,7 @@ from fastapi.responses import FileResponse, JSONResponse
 from fastapi.staticfiles import StaticFiles
 
 from kilostar.utils.standalone_proxy import _STANDALONE
+from kilostar.utils.settings import get_settings
 
 if not _STANDALONE:
     from ray import serve
@@ -51,13 +52,13 @@ _api_logger = get_logger("api")
 
 
 def _get_locale(request: Request) -> str | None:
-    """从请求头解析首选语言，供异常 handler 使用。"""
     return request.headers.get("accept-language") or None
 
 app = FastAPI()
 
-_cors_origins_env = os.environ.get("KILOSTAR_CORS_ORIGINS", "")
-_is_dev = os.environ.get("KILOSTAR_ENV", "production").lower() in ("dev", "development")
+_settings = get_settings()
+_cors_origins_env = _settings.kilostar_cors_origins
+_is_dev = _settings.security.kilostar_env.lower() in ("dev", "development")
 if not _cors_origins_env and _is_dev:
     _cors_origins_env = "*"
 elif not _cors_origins_env: