将 postgresql_info.py 移出 native/，合并到 core/config.py 或 infra/db/，便于后续项目环境变量读取发生变化

app/core/config.py

@@ -1,4 +1,5 @@
 from pathlib import Path
+from typing import Optional
 from urllib.parse import quote_plus
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
@@ -80,3 +81,37 @@ class Settings(BaseSettings):
 
 
 settings = Settings()
+
+
+def get_pgconn_string(
+    db_name: Optional[str] = None,
+    db_host: Optional[str] = None,
+    db_port: Optional[str] = None,
+    db_user: Optional[str] = None,
+    db_password: Optional[str] = None,
+) -> str:
+    """Return PostgreSQL connection string in psycopg conninfo format."""
+    resolved_db_name = db_name or settings.DB_NAME
+    resolved_db_host = db_host or settings.DB_HOST
+    resolved_db_port = db_port or settings.DB_PORT
+    resolved_db_user = db_user or settings.DB_USER
+    resolved_db_password = db_password or settings.DB_PASSWORD
+    return (
+        f"dbname={resolved_db_name} host={resolved_db_host} port={resolved_db_port} "
+        f"user={resolved_db_user} password={resolved_db_password}"
+    )
+
+
+def get_pg_config() -> dict:
+    """Return PostgreSQL configuration except password."""
+    return {
+        "name": settings.DB_NAME,
+        "host": settings.DB_HOST,
+        "port": settings.DB_PORT,
+        "user": settings.DB_USER,
+    }
+
+
+def get_pg_password() -> str:
+    """Return PostgreSQL password (use with care)."""
+    return settings.DB_PASSWORD