Returns the cross-tenant reconciliation plan: every account that has any department row or any copilot_config row, with its departments (active AND passive) and per-brand Copilot desk selections.

Response for GET /api/ai/kb-sync-plan — the cross-tenant reconciliation plan the helpdesk-updater pulls to decide which knowledge-base departments to keep, purge, or resync per account. Desk→department mapping is intentionally NOT here: it lives in the helpdesk service and the updater fetches it there. This endpoint is DB-only.

Both serializer attributes are present on every field: Infoset.Api serializes with Newtonsoft.Json (AddNewtonsoftJson in Startup), so [JsonProperty] drives the wire shape, while [JsonPropertyName] keeps System.Text.Json consumers (ad-hoc test deserialisers) in sync. camelCase matches the sibling internal responses.