fix: restore message migration CI coverage

packages/llm/llm-pi-ai/src/replay.ts

@@ -9,7 +9,7 @@
  */
 
 import { LlmError } from '@deepseek-ai/dsh-llm'
-import type { Message } from '@deepseek-ai/dsh-llm'
+import type { Message, ModelMessageSource } from '@deepseek-ai/dsh-llm'
 import type { Api, AssistantMessage, Usage as PiUsage } from '@earendil-works/pi-ai'
 
 type PiAiReplayBlock =
@@ -155,10 +155,8 @@ function foreignAssistant(message: Message): AssistantMessage {
 }
 
 /** Recombine durable Harness content with validated pi-ai replay metadata. */
-function replayedAssistant(message: Message, rawState: unknown): AssistantMessage {
+function replayedAssistant(message: Message, source: ModelMessageSource, rawState: unknown): AssistantMessage {
   const state = readReplayState(rawState)
-  const source = message.source
-  if (source.kind !== 'model') return invalidReplay('assistant message lacks model source')
   if (state.provider !== source.provider) return invalidReplay('provider does not match assistant source')
   if (state.model !== source.model) return invalidReplay('model does not match assistant source')
   if (state.blocks.length !== message.content.length) return invalidReplay('block count does not match assistant content')
@@ -208,6 +206,8 @@ function replayedAssistant(message: Message, rawState: unknown): AssistantMessag
  * @returns a native pi-ai assistant message reconstructed from durable content.
  */
 export function toPiAssistant(message: Message): AssistantMessage {
-  const replayState = message.source.kind === 'model' ? message.source.replayState : undefined
-  return replayState === undefined ? foreignAssistant(message) : replayedAssistant(message, replayState)
+  const source = message.source
+  return source.kind !== 'model' || source.replayState === undefined
+    ? foreignAssistant(message)
+    : replayedAssistant(message, source, source.replayState)
 }

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

@@ -102,6 +102,24 @@ describe('toPiContext', () => {
     expect((context.messages[0] as AssistantMessage).stopReason).toBe('stop')
   })
 
+  it('preserves model provenance for foreign assistant messages without replay state', () => {
+    const context = toPiContext({
+      provider: 'openai',
+      model: 'new-model',
+      messages: [createMessage({
+        role: 'assistant',
+        content: [{ type: 'text', text: 'done' }],
+        source: { kind: 'model', provider: 'deepseek', model: 'old-model' },
+      })],
+    })
+    expect(context.messages[0]).toMatchObject({
+      role: 'assistant',
+      api: 'dsh-foreign',
+      provider: 'deepseek',
+      model: 'old-model',
+    })
+  })
+
   it('parses malformed tool-call arguments to {}', () => {
     const context = toPiContext({
       provider: 'deepseek',