fix(headless): dsh run is a direct core front door

packages/host/apiproxy/tests/api-proxy-fork.spec.ts

@@ -82,7 +82,7 @@ function liveAgent(
 }
 
 const api = (ctx: Context) => createApiProxy(ctx, {
-  defaultTarget: () => ({ provider: 'default-provider', model: 'default-model' }),
+  defaultModelSelection: () => ({ provider: 'default-provider', model: 'default-model' }),
   cwd: '/tmp',
   workspaceRoot: '/tmp',
 })
@@ -254,7 +254,7 @@ describe('sessions.fork', () => {
     await ctx.fiber.dispose()
   })
 
-  it('installs the latest logged model target before the child can run', async () => {
+  it('installs the latest logged model selection before the child can run', async () => {
     const ctx = await composed()
     const source = liveAgent(ctx, 'session-routed', 1)
     source.append('request/header', {