refactor: identify and freeze messages at creation

packages/llm/llm-pi-ai/tests/adapter.spec.ts

@@ -2,7 +2,7 @@ import { createServer } from 'node:http'
 import type { IncomingMessage, Server, ServerResponse } from 'node:http'
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
-import LlmService, { CONTEXT_WINDOW_EXCEEDED_CODE, LlmError, ReasoningEffortId, userAgent } from '@deepseek-ai/dsh-llm'
+import LlmService, { createUserMessage, CONTEXT_WINDOW_EXCEEDED_CODE, LlmError, ReasoningEffortId, userAgent  } from '@deepseek-ai/dsh-llm'
 import * as LlmPiAi from '@deepseek-ai/dsh-llm-pi-ai'
 import { PiAiAdapter } from '@deepseek-ai/dsh-llm-pi-ai'
 import { MAX_TIMER_DELAY_MS } from '@deepseek-ai/dsh-timeout'
@@ -103,7 +103,10 @@ describe('PiAiAdapter provider routing', () => {
     const ctx = await harness(server.url)
     const result = await assemble(ctx, {
       model: 'deepseek-v4-flash',
-      messages: [{ role: 'user', content: [{ type: 'text', text: 'hi' }] }],
+      messages: [createUserMessage({
+        content: [{ type: 'text', text: 'hi' }],
+        source: { kind: 'plugin', plugin: 'test' },
+      })],
     })
     expect(result.message.content).toEqual([{ type: 'text', text: 'hello' }])
     expect(result.finish).toEqual({ kind: 'stop' })