refactor: align backend with company-site-member schema and system-level RBAC groups

backend/app/repositories/systems_repo.py

@@ -0,0 +1,33 @@
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from app.models.system import System
+
+
+class SystemsRepository:
+    def __init__(self, db: Session) -> None:
+        self.db = db
+
+    def get_by_key(self, system_key: str) -> System | None:
+        stmt = select(System).where(System.system_key == system_key)
+        return self.db.scalar(stmt)
+
+    def get_by_id(self, system_id: str) -> System | None:
+        stmt = select(System).where(System.id == system_id)
+        return self.db.scalar(stmt)
+
+    def list(self, status: str | None = None, limit: int = 100, offset: int = 0) -> tuple[list[System], int]:
+        stmt = select(System)
+        count_stmt = select(func.count()).select_from(System)
+        if status:
+            stmt = stmt.where(System.status == status)
+            count_stmt = count_stmt.where(System.status == status)
+        stmt = stmt.order_by(System.created_at.desc()).limit(limit).offset(offset)
+        return list(self.db.scalars(stmt).all()), int(self.db.scalar(count_stmt) or 0)
+
+    def create(self, system_key: str, name: str, status: str = "active") -> System:
+        item = System(system_key=system_key, name=name, status=status)
+        self.db.add(item)
+        self.db.commit()
+        self.db.refresh(item)
+        return item