fix(compute): /opc/compute/base 与 tokens 500 修复

- base: request.base_url 是 URL 对象无 rstrip, 改 str(...).rstrip
- tokens: list_user_tokens 现返回列表, 兼容 list/dict
- 修复 OPC 桌面端算力中心 Base API 地址与令牌列表 500(此前 500→前端空/失败)

app/api/routers/rbac_opc.py

@@ -223,7 +223,7 @@ async def opc_compute_base(
     user: dict = Depends(require_roles("opc_member")),
 ):
     """用户接入地址：经 server-core /v1 中继（OpenAI 兼容）。优先用公网配置，回落请求 host。"""
-    base = config.COMPUTE_PUBLIC_BASE or request.base_url.rstrip("/")
+    base = config.COMPUTE_PUBLIC_BASE or str(request.base_url).rstrip("/")
     base = base.rstrip("/")
     return {
         "base_url": f"{base}/v1",
@@ -251,7 +251,8 @@ async def opc_compute_tokens(user: dict = Depends(require_roles("opc_member"))):
         data = await compute_client.list_user_tokens(user.get("username"))
     except compute_client.ComputeError as exc:
         raise HTTPException(status_code=502, detail=f"算力引擎对接失败: {exc}") from exc
-    return {"items": data.get("items", [])}
+    items = data if isinstance(data, list) else data.get("items", [])
+    return {"items": items}
 
 
 @router.post("/compute/tokens", summary="创建算力令牌")