fix(mobile-chat): require image provenance for glued prefix matches

mobile/src/session/mobile-native-chat-draft-reconcile.test.ts

@@ -73,6 +73,19 @@ describe('mobile native chat image preview reconciliation', () => {
     expect(findLandedImagePreviewEchoes(messages, [preview])).toEqual([])
   })
 
+  it('does not bind a glued image echo to an ordinary row with the same prefix', () => {
+    const messages = [
+      userText('ordinary', 'look at this later'),
+      userText('source', '[Image: source: /tmp/a.png]'),
+      userText('prompt', 'look at this[Image #1] is it still working?')
+    ]
+    const preview = { ...pending('pending', ['file:///a.jpg']), text: 'look at this' }
+
+    expect(findLandedImagePreviewEchoes(messages, [preview])).toEqual([
+      { pendingId: 'pending', messageId: 'prompt', images: ['file:///a.jpg'] }
+    ])
+  })
+
   it('reconciles a middle-marker echo without changing its rendered whitespace', () => {
     const messages = [
       userText('source', '[Image: source: /tmp/a.png]'),

mobile/src/session/mobile-native-chat-draft-reconcile.ts

@@ -153,6 +153,20 @@ export function findLandedImagePreviewEchoes(
 ): LandedImagePreviewEcho[] {
   const normalized = normalizeImageTranscriptMessages(messages)
   const messageIndexById = new Map(normalized.map((message, index) => [message.id, index]))
+  // Keep provenance from the raw transcript: normalization removes image markers,
+  // so a plain text row must not become a candidate merely because it shares a
+  // caption prefix with a glued image send.
+  const imageMessageIds = new Set(
+    messages
+      .filter(
+        (message) =>
+          message.role === 'user' &&
+          (isImageSourceUserTurn(message) ||
+            hasImagePromptMarker(message) ||
+            message.blocks.some(isImageRefBlock))
+      )
+      .map((message) => message.id)
+  )
   const claimedMessageIds = new Set<string>()
   const landed: LandedImagePreviewEcho[] = []
 
@@ -175,7 +189,9 @@ export function findLandedImagePreviewEchoes(
         // text-only send lands in a row whose text is the concatenation. Requiring the
         // whole row to equal this echo left it unmatched, and since both other
         // retirement paths skip image echoes, nothing could ever retire it.
-        return text === targetText || text.startsWith(targetText)
+        return (
+          text === targetText || (imageMessageIds.has(message.id) && text.startsWith(targetText))
+        )
       }
       const imageCount = message.blocks.filter(isImageRefBlock).length
       return message.blocks.length === 0 || imageCount >= entry.images!.length