fix(mobile): preserve queued image preview on WAL adoption

mobile/src/session/mobile-structured-session-timeline.test.ts

@@ -91,6 +91,30 @@ describe('mobile structured session timeline', () => {
     expect(rows[0]).toMatchObject({ key: wal.itemId, outbox: { state: 'unconfirmed' } })
   })
 
+  it('keeps the device-local thumbnail on the adopted row while delivery is unconfirmed', () => {
+    const wal: AgentJournalRenderItem = {
+      itemId: agentJournalSubmissionKey(OUTBOX.clientMessageId),
+      revision: 1,
+      sequence: 1,
+      observedAt: 3,
+      body: OUTBOX.body
+    }
+
+    const rows = buildMobileStructuredTimeline([wal], [OUTBOX])
+
+    expect(rows).toHaveLength(1)
+    expect(rows[0]).toMatchObject({
+      key: wal.itemId,
+      outbox: { state: 'unconfirmed' },
+      message: {
+        blocks: [
+          { type: 'text', text: 'look' },
+          { type: 'image-ref', url: 'file:///preview.png' }
+        ]
+      }
+    })
+  })
+
   it('restores host paths and local previews when a queued send is edited', () => {
     expect(restoreMobileStructuredAttachments(OUTBOX)).toEqual([
       {

mobile/src/session/mobile-structured-session-timeline.ts

@@ -26,22 +26,29 @@ function isPendingPrompt(item: AgentJournalRenderItem): item is MobileStructured
 }
 
 function outboxMessage(entry: MobileStructuredOutboxEntry): NativeChatMessage {
-  let imageIndex = 0
   return {
     id: entry.clientMessageId,
     role: 'user',
     timestamp: entry.queuedAt,
     source: 'transcript',
-    blocks: entry.body.blocks.map((block) => {
-      if (block.type !== 'image-ref') {
-        return block
-      }
-      const preview = entry.previewUris[imageIndex++]
-      return preview ? { ...block, url: preview, path: undefined } : block
-    })
+    blocks: mobilePreviewBlocks(entry.body.blocks, entry.previewUris)
   }
 }
 
+function mobilePreviewBlocks(
+  blocks: NativeChatMessage['blocks'],
+  previewUris: readonly string[]
+): NativeChatMessage['blocks'] {
+  let imageIndex = 0
+  return blocks.map((block) => {
+    if (block.type !== 'image-ref') {
+      return block
+    }
+    const preview = previewUris[imageIndex++]
+    return preview ? { ...block, url: preview, path: undefined } : block
+  })
+}
+
 export function buildMobileStructuredTimeline(
   items: readonly AgentJournalRenderItem[],
   outbox: readonly MobileStructuredOutboxEntry[]
@@ -67,7 +74,16 @@ export function buildMobileStructuredTimeline(
     if (entry) {
       seen.add(entry.clientMessageId)
     }
-    return [{ kind: 'message', key: message.id, message, ...(entry ? { outbox: entry } : {}) }]
+    return [
+      {
+        kind: 'message',
+        key: message.id,
+        message: entry
+          ? { ...message, blocks: mobilePreviewBlocks(message.blocks, entry.previewUris) }
+          : message,
+        ...(entry ? { outbox: entry } : {})
+      }
+    ]
   })
   return [
     ...canonical,