Returns the resolved configuration for one `(accountId, departmentId)` pair. 404 when the brand has no row — deliberately not a 200 carrying `enabled: false`. The caller treats 404 as "disabled, cache the negative", which is cheaper and unambiguous. A row that was explicitly switched off does return 200 with `enabled: false`.

Read DTO for the gen-ai interactive support agent configuration. Returned by both the admin endpoint (/v1/admin/genai/config) and the internal endpoint (/api/genai/config).

Every tuning field here is the EFFECTIVE value, already resolved server-side: the brand's own override, else the brand's copilot row, else the platform default. A consumer never has to know the layering existed, and never has to look anything up of its own.

There is no defaults DTO: a brand with no row yields no DTO at all. That is the deliberate divergence from Infoset.Types.Models.Admin.CopilotConfigDto, whose service fabricates one when nothing is persisted — here, "never configured" must stay distinguishable from "configured and off".