fix: fetch dataset scope options from WorldQuant platform

backend/app/catalog/platform.py

@@ -0,0 +1,30 @@
+"""Shared platform scope discovery for HTTP and AI consumers."""
+
+from fastapi import HTTPException
+
+from ..worldquant import WqError
+
+
+async def platform_options(client):
+    """Return live account choices, surfacing sanitized upstream failures to callers."""
+    if client is None:
+        raise HTTPException(409, "请先连接 WorldQuant")
+    try:
+        return await client.get_platform_setting_options()
+    except WqError as exc:
+        raise HTTPException(
+            409 if exc.code in ("disconnected", "verification_required") else 502, str(exc)
+        ) from None
+
+
+async def validate_platform_scope(client, scope):
+    """Reject unsupported combinations before creating a synchronization job."""
+    data = await platform_options(client)
+    if not any(
+        row["instrument_type"] == scope.instrument_type
+        and row["region"] == scope.region
+        and row["delay"] == scope.delay
+        and scope.universe in row["universes"]
+        for row in data["instrument_options"]
+    ):
+        raise HTTPException(422, "平台不支持此 Instrument Type / Region / Delay / Universe 组合")