fix(mobile): isolate image echo occurrences by count

(cherry picked from commit c51e8e6bbb)

mobile/src/session/mobile-native-chat-literal-marker-echo.test.ts

@@ -198,4 +198,46 @@ describe('mobile literal image-marker turns', () => {
       ['file:///a.jpg', 'file:///b.jpg', 'file:///c.jpg']
     ])
   })
+
+  it('reconciles rapid equal captions in separate image-count namespaces', async () => {
+    await mount()
+    send('compare', ['file:///a.jpg'])
+    send('compare', ['file:///b.jpg', 'file:///c.jpg', 'file:///d.jpg'])
+
+    const messages = [
+      userTextMessage('source-a', '[Image: source: /tmp/a.png]'),
+      userTextMessage('prompt-a', 'compare [Image #1]'),
+      userTextMessage('source-b', '[Image: source: /tmp/b.png]'),
+      userTextMessage('source-c', '[Image: source: /tmp/c.png]'),
+      userTextMessage('source-d', '[Image: source: /tmp/d.png]'),
+      userTextMessage('prompt-b', 'compare [Image #1] [Image #2] [Image #3]')
+    ]
+    await transcript(messages)
+
+    const rendered = rows(messages)
+    expect(rendered).toHaveLength(2)
+    expect(rendered.map(rowImages)).toEqual([
+      ['file:///a.jpg'],
+      ['file:///b.jpg', 'file:///c.jpg', 'file:///d.jpg']
+    ])
+  })
+
+  it('reconciles rapid captionless sends in separate image-count namespaces', async () => {
+    await mount()
+    send('', ['file:///a.jpg'])
+    send('', ['file:///b.jpg', 'file:///c.jpg', 'file:///d.jpg'])
+
+    const messages = [
+      userTextMessage('prompt-a', '[Image #1]'),
+      userTextMessage('prompt-b', '[Image #1] [Image #2] [Image #3]')
+    ]
+    await transcript(messages)
+
+    const rendered = rows(messages)
+    expect(rendered).toHaveLength(2)
+    expect(rendered.map(rowImages)).toEqual([
+      ['file:///a.jpg'],
+      ['file:///b.jpg', 'file:///c.jpg', 'file:///d.jpg']
+    ])
+  })
 })

mobile/src/session/mobile-native-chat-pending-echo.ts

@@ -52,13 +52,16 @@ export function appendMobileNativeChatPending(
   const earlierOutstanding = current.filter(
     (pending) =>
       pendingMatchText(pending) === origin.normalizedText &&
+      (pending.images?.length ?? 0) >= origin.imageCount &&
       pending.expectedOccurrence > origin.baselineOccurrences
   ).length
   // An image send whose caption is only markers still reconciles by image
   // ordinal, matching how `captureSendOrigin` normalized it.
   const expectedImageEchoOrdinal =
     current.filter(
-      (pending) => pending.images?.length && normalizeNativeChatUserText(pending.text) === ''
+      (pending) =>
+        (pending.images?.length ?? 0) >= origin.imageCount &&
+        normalizeNativeChatUserText(pending.text) === ''
     ).length + 1
   return {
     ...previous,