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/core/postgres_database/database_exception.py

@@ -14,7 +14,7 @@
 
 from sqlalchemy.exc import IntegrityError, OperationalError
 from pydantic import ValidationError
-from kilostar.utils.error import UserNotExistError
+from kilostar.utils.error import UserNotExistError, BusinessError, RetryableError
 
 from kilostar.utils.logger import get_logger
 
@@ -31,14 +31,16 @@ def database_exception(func):
             logger.error(f"对象校验失败:{e}")
             raise e
         except IntegrityError as e:
-            logger.error(f"数据库完整性错误 (如重复记录): {e}")
-            raise e
+            logger.warning(f"数据库完整性冲突: {e.orig}")
+            err = BusinessError(str(e.orig))
+            err.http_status = 409
+            err.code = "conflict"
+            raise err from e
         except OperationalError as e:
             logger.error(f"数据库连接异常: {e}")
-            raise e
-        except UserNotExistError as e:
-            logger.error(f"更改密码失败，用户不存在：{e}")
-            raise e
+            raise RetryableError(f"数据库暂时不可用，请稍后重试: {e}") from e
+        except (UserNotExistError, BusinessError):
+            raise
         except Exception as e:
             logger.exception(f"未预期的数据库错误: {e}")
             raise e