refactor(agent): own model selection on each agent

packages/api/session-controller/tests/controller.host.spec.ts

@@ -2,7 +2,6 @@ import SessionProjectionRegistry from '@deepseek-ai/dsh-session-projection'
 import { Context } from '@deepseek-ai/cordis'
 import AgentRegistry from '@deepseek-ai/dsh-agent'
 import type { Agent } from '@deepseek-ai/dsh-agent'
-import * as AgentModelPlugin from '@deepseek-ai/dsh-agent-model'
 import { createUserMessage } from '@deepseek-ai/dsh-llm'
 import SessionStore, { SESSION_FORMAT_VERSION, SessionId, SessionLogOffset } from '@deepseek-ai/dsh-session'
 import type { SessionEvent, SessionHeader } from '@deepseek-ai/dsh-session'
@@ -26,7 +25,6 @@ describe('SessionController facade', () => {
     const ctx = new Context()
     await ctx.plugin(SessionStore)
     await ctx.plugin(SessionProjectionRegistry)
-    await ctx.plugin(AgentModelPlugin)
     await ctx.plugin(AgentRegistry)
     const sessionId = SessionId('controller-session')
     const header: SessionHeader = {