fix(models): attach provider to inline model definitions

When resolving models from custom provider configurations, ensure the
provider name is attached to each inline model entry. This fixes model
resolution for custom providers where the model definition exists in
the config but lacks an explicit provider field.

Without this fix, inline models from custom providers (like amazon-bedrock)
would fail to resolve because the provider context was lost during the
flatMap operation.

src/agents/pi-embedded-runner/model.ts

@@ -39,7 +39,7 @@ export function resolveModel(
   if (!model) {
     const providers = cfg?.models?.providers ?? {};
     const inlineModels =
-      providers[provider]?.models ??
+      providers[provider]?.models?.map((entry) => ({ ...entry, provider })) ??
       Object.values(providers)
         .flatMap((entry) => entry?.models ?? [])
         .map((entry) => ({ ...entry, provider }));