bug: /v1/cost/summary ignores from/to query params

[OneStepAt4time]

Bug Report

Priority: P2

Description:
/v1/cost/summary ignores from/to query parameters. Sending ?from=2026-05-13T00:00:00Z&to=2026-05-14T00:00:00Z returns "from": null, "to": null. The /v1/cost/by-model endpoint correctly parses the same params — the summary endpoint's query parsing is broken.

Steps to reproduce:

curl -H "Authorization: Bearer $TOKEN" "http://127.0.0.1:9100/v1/cost/summary?from=2026-05-13T00:00:00Z&to=2026-05-14T00:00:00Z"

Returns "from": null, "to": null instead of the filtered range.

Found by: Daedalus (dogfooding, 2026-05-14)

[OneStepAt4time]

Fixed by #3311 (merged to develop).