feat(id): brand ProviderID and ModelID (#17110)

packages/opencode/src/agent/agent.ts

@@ -1,6 +1,7 @@
 import { Config } from "../config/config"
 import z from "zod"
 import { Provider } from "../provider/provider"
+import { ModelID, ProviderID } from "../provider/schema"
 import { generateObject, streamObject, type ModelMessage } from "ai"
 import { SystemPrompt } from "../session/system"
 import { Instance } from "../project/instance"
@@ -34,8 +35,8 @@ export namespace Agent {
       permission: PermissionNext.Ruleset,
       model: z
         .object({
-          modelID: z.string(),
-          providerID: z.string(),
+          modelID: ModelID.zod,
+          providerID: ProviderID.zod,
         })
         .optional(),
       variant: z.string().optional(),