The data layer the resource tabs build on:
- apis/resource.ts: adapter over the unified metered_usage read API
(resource/gpu-instances/storage/summary/events breakdowns), flattening
the server's generic shape into the per-tab item shape.
- hooks/use-resource-meta.ts: loads creators/instances/volumes filter
options for the current scope.
- utils/time-buckets.ts: day/week/month/hour bucket keys + range fill.
- utils/export-breakdown.ts: derive Excel columns from antd table specs.
Align with gpustack backend commits 7b57cd3b (add route dimension to
usage breakdown) and 51fd25c8 (use model_route_id as models_called):
* group_by, filters, and BreakdownItem now use the `route` dimension;
`models` filter cascader is replaced with a flat `routes` selector
(routes have no provider/cluster grouping).
* Tab / group_by option / column header keep the user-facing "模型 / Model"
wording — only the underlying data dimension changed.
* Drop cluster_name / provider_type columns from the breakdown table;
drop api_keys_used column per design.
* Fix pre-existing excel export bug in use-export-table — string
dataIndex was lodash-joined char-by-char ("input_tokens" →
"i_n_p_u_t..."), array dataIndex was used as a flat key against nested
rows. Rebuilt around buildSheetMeta that emits a stable field key plus
a formatMap using _.get(row, path) for nested values. Sheet name kept
as `models` to match the visible column label.
