feat: add export route skeleton

surfsense_backend/app/routes/export_routes.py

@@ -0,0 +1,38 @@
+"""Routes for exporting knowledge base content as ZIP."""
+
+import logging
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.db import Permission, User, get_async_session
+from app.users import current_active_user
+from app.utils.rbac import check_permission
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+@router.get("/search-spaces/{search_space_id}/export")
+async def export_knowledge_base(
+    search_space_id: int,
+    folder_id: int | None = Query(None, description="Export only this folder's subtree"),
+    session: AsyncSession = Depends(get_async_session),
+    user: User = Depends(current_active_user),
+):
+    """Export documents as a ZIP of markdown files preserving folder structure.
+
+    If folder_id is provided, only that folder's subtree is exported.
+    Otherwise, the entire search space is exported.
+    """
+    await check_permission(
+        session,
+        user,
+        search_space_id,
+        Permission.DOCUMENTS_READ.value,
+        "You don't have permission to export documents in this search space",
+    )
+
+    # TODO: implement export logic
+    return {"message": "Export endpoint placeholder"}