### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

**What happened** On the admin UI **Usage** page (Cost tab, Global Usage), the page renders briefly then dies with **"This page couldn't load."** Browser console:

``` Uncaught TypeError: Cannot read properties of undefined (reading 'spend') at <usage chunk> (Array.forEach → Array.forEach, inside a useMemo) ```

The crashing line is the top-keys aggregation: ```js e[t].metrics.spend += s.metrics.spend // s.metrics is undefined ``` `s.metadata` (key_alias, tags) is present but `s.metrics` is undefined for one entry.

**Root cause (traced)** The page fetches only **page 1** of `/user/daily/activity` (`page_size=1000&page=1`), but on our deployment the response is **36 pages** — page 1 returns just **1 of the 7 requested days**. The client-side aggregation then runs over **incomplete data** and hits an entry whose `metrics` didn't come through on page 1 → `s.metrics.spend` throws.

It is **data-state dependent**: crashes on a large/populated dataset, renders fine on a small one (e.g. a low-traffic staging env). The backend data itself is we…