refactor: support explicit provider field in model list entries (#2609)

* refactor: support explicit model list providers

* fix(web): preserve explicit model providers

* fix(web): preserve legacy provider prefixes on model updates

fix(models): normalize explicit provider-prefixed ids

fix(api): preserve legacy model updates across providers

fix(agent): preserve config identity for explicit provider refs

* fix ci

web/frontend/src/api/models.ts

@@ -6,6 +6,7 @@ import { refreshGatewayState } from "@/store/gateway"
 export interface ModelInfo {
   index: number
   model_name: string
+  provider?: string
   model: string
   api_base?: string
   api_key: string